Introduction
Many regulated river systems support several resource assessment schemes to share the available resource (water) among users. In Source, a resource assessment system:
- is associated with only one scenario in a project, whereas a scenario may be associated with one or more resource assessment systems;
- can only have one owner, but any given owner or water user may be affected by more than one system; and
- supports multiple account types.
Note that resource assessment only operates correctly in a regulated system.
Figure 1 shows the various contextual menus available for each level in the resource assessment hierarchy. Note that similar types of accounts or systems have the same contextual menu. For example, all off-allocation systems have the same contextual menu, and all account types follow a similar trend.
Figure 1. Resource Assessment Explorer
In practice there are a number of resource assessment methodologies used, which can be implemented in Source using a generic resource assessment tool, referred to as Simple Water Accounting. The next section provides details on configuring two types of resource assessment in Source - general and continuous sharing.
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For detailed information about resource assessment, refer to the Source Scientific Reference Guide. To enable General Resource Assessment:
- Choose from the Source main menu t open the Resource Assessment Explorer (Figure 1);
- Click the disclosure triangle to the left of the scenario name and choose Add Simple System from the contextual menu.
You can edit the system name by right clicking on the name and choosing Rename from the contextual menu. Type in the field and press the carriage-return.
Once a system has been added (Figure 2), provide the following details:
- Set the System Owner. There can only be one owner per system; and
- Set the Water Year Start date. The system will run for 365 days from the date set.
The Accounts and Triggers tabs provide an overview of these items that have been added (generally under Account Type).
You can also assign different storages to various resource assessment systems using the Assigned Storages panel on the right. Enable the storage that you wish to add to a particular resource assessment system.
You can also configure an off-allocation system, an account type or a trigger by right-clicking the system name and choosing one from the contextual menu.
Figure 2. Simple system
Adding an account type
A system may contain several account types, each consisting of many accounts that have common properties. With resource assessment, you can group accounts according to different levels of water security, or any other common criteria appropriate to a set of accounts.
To add a new account type, click on the Accounts tab (Figure 2). Then, click Add Account Type. If desired, you can edit the account type name to be more meaningful.
Figure 2. Simple system (Account type, Configuration)
When an account type is selected, the right hand panel displays two tabs - Configuration and Accounts. The former (shown in Figure 2) is a summary of operating information for each account type. In the Allocation panel, account allocations are made as a single value, using either a time series (Data Sources) or an expression (Function Editor). Note that allocation data is interpreted as a cumulative volume allocated per unit share. This means that accounts are only credited if there is an increase in allocation volume since the previous time-step. An account is credited by calculating the increased volume multiplied by the number of shares that the account has in the resource assessment system. The latter lists all the accounts currently configured in the system (similar to the dialog shown in Figure number). The parameters in the Accounts table are explained in Table 3.
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In the Resource Assessment Explorer window (shown in Figure 3), right-click on the Account Type in the left hand panel and choose Add Account from the contextual menu. This is applicable to all dialogs in the Resource Assessment Explorer where you can add or delete accounts.
You can configure the properties of an account using the panel displayed in Figure 3. Note that:
- Each account can have only one water user associated with it;
- You must enter the number of shares that the account has in the resource assessment system; and
- You can specify an opening account balance.
Figure 3. Simple system (Account type, Add new account)
Usage limits
You can limit water usage for all accounts by absolute volume or a per-unit-share, which can cover a water year or movable time window (shown in Figure7). You can define any number of usage limits.
- To add a usage limit, right click on Account Type and choose Add Usage Limit;
- To delete a usage limit, right click on it, and choose Delete; and
- You can also rename it using the contextual menu.
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| Note: The usage limit, regardless of its position in the hierarchy, requires the same parameters to be configured. Figure 4 is therefore the same for all invocations of usage limit. |
Figure 4. Simple system (Account type, Usage limit)
Account type triggers
A trigger initiates or cancels certain actions for an account type and can be configured using the panel shown in Figure 5. To set up a trigger, right-click the account type on the left hand panel and choose Add trigger.
Triggers can be set to activate on a particular date, a year start or end or the passing (either raising or falling) through a specified storage water level. When a trigger is activated it will initiate a pre-defined action, which is defined in the panel on the right hand side of the Triggers window. Possible actions include:
- Transferring a percentage of water to another account;
- Levelling accounts;
- Writing off accounts; and
- Truncating or assigning accounts.
An account type can have several triggers, each designed to initiate a particular action.
Figure 5. Simple system (Account type, Trigger)
Annual Accounting
Annual accounting is a custom assessment method for regulated water in resource assessment module. For an annual accounting system, the general principles are:
- An available resource is calculated during a defined water year;
- Allocation of the resource are made to different account types;
- Each account type’s allocation are distributed between accounts linked to this account type;
- Any allocated water that has not been carried over at the end of the defined water year will be returned to the available resource for allocations of next year.
An annual accounting system works in Source follows these principles.
Add Account Type
An annual accounting may contain several account types. Each account type can also include many accounts. Right click Annual Accounting 1, An annual accounting system may contain several account types. Each account type can also include many accounts. Right click Annual Accounting 1 and choose add account type.
There are six submenu in the drop down menu: add account, add trigger, add usage limit, rename, delete and collapse.
Add Account
To add an account, right click the name you have allocated, and choose Add account. You can rename the account at this point. It is best to choose a name for the account associated with the node, or 'account host' that it will be used for.
Set number of shares, initial account balance and previous usage. Previous usage can also be set by a function also if users click the ellipsis beside it. Select the water user to link the account to in associated account host. The associated account lists all the water user nodes built in this project. Each account can have only one water user associated with it.
Figure 6. Configuring Accounts
Once the number of shares are set, go to the schematic editor window, right click the water user and choose “edit” to open the editor window. Click Distribution from the left hand panel, then click account sharing from the right hand panel. Details of account distribution and supply point will be shown. Unit shares will automatically be shown here if they were set in the resource assessment panel. Debit Type is also got automatically from configuration of annual accounting. Priority and Share Ratio are editable here.
Priority 1 is the highest level. The share ratios of Accounts with the same priority level should sum to 100%. More details can be found in the user guide Water User Node.
Add trigger
Triggers can be added at any level under Annual Accounting. Right click the account and choose Add trigger. A trigger initiates or cancels certain actions for an account and can be configured using the properties panel shown in Figure 5. Users can also edit functions for a trigger. For example, if “Function” is chosen for trigger configuration, a function is needed to initiate an action. The format of a function should be like this: “IF A>B, 1, 0”, where “1” indicates the action will occur and “0” means the action will not happen.
An account can have several triggers, each can be designed to initiate a particular action. Right click trigger, users can choose rename or delete to rename or delete this trigger from the drop-down menu. After triggers are set up, users can set triggers’ priorities by moving them up and down in Trigger Priority.
Add usage limit
Right click the account or account type and choose Add usage limit, see Figure 4. Users can limit water usage for all accounts by absolute volume or per-unit-share for moving water year or movable time window (Figure 4). An account can have several usage limits, each can be designed to initiate a particular limit. Right click usage limit, users can choose rename or delete to rename or delete this usage limit from the drop-down menu.
Configuration of Account Type
When account, trigger and water usage limit are all set up, you can go back to account type to configure and see summary information of all added accounts.
Click Account Type on the left hand panel, and make sure the configuration tab is selected on the right (Figure 2), set debit type, priority, minimum and maximum balance, minimum and maximum volume. If they are non-debit accounts, you need to tick the box Enable non-debit accounts, and then the availability threshold and repayment threshold become editable.
For allocation calculation method, there are two options from the allocation calculation drop down menu (Figure 2). One is as a function, where you can determine an account type’s allocation. The other is by using an available resource allocation table (ARA table). This function may reference a wide range of variables available in the model, including allocations to other account types and resource assessment systems. If an ARA table is chosen (Figure 7), configuration options will display for you to set detailed information.
Figure 7 Configuring Allocation Calculation Model
There are five methods can be chosen form the drop-down menu of method to apply for this account type in ARA table (Figure 7):
Function You set the function at this level.
Monthly varying You can set the calculation method as either interpolate or threshold.
Percent (with Function) This is similar to percent (with linked volume), difference exists at the annual accounting level allocation page which is discussed somewhere.
Percent (with linked volume) The default option for method to apply for this account type in ARA table. You can set Announced Increment, Maximum Announced Percent and Shares. If Use Shares from Accounts is ticked, Shares will get value automatically from account shares which is set at the account (rather than the account type) level.
Volumetric. You will need to set the volume at the annual accounting level allocation page which is discussed somewhere.
Accounts summary at Account Type Level
Clicking on the Accounts tab beside configuration at the top of the right hand panel (Figure 7), will show all the accounts created under this Account type.
You can also add an account simply by click the Add Account button below the list, or delete an account by selecting the account that to be deleted and clicking the Delete Account button. The Unit Shares and Initial Balance values are transferred automatically from the account but can also be edited here (Figure 7b).
Figure 7b. Accounts Summary Tab
Add an Off-Allocation System
Off-Allocation Systems are assigned at the top Annual Accounting level. Right click annual accounting and choose add off-allocation system from the drop-down menu. An off-allocation system can be configured using the properties panel shown in Figure 13. Detailed information of off-allocation system can be found under Off-Allocation Node
Configuration of Annual Accounting and Summary of accounts, allocation and trigger Priority
After account type and triggers are set up, you can go back to annual accounting to
- configure annual accounting
- see summary information of all accounts added
- set the available resource vs allocation table
- set trigger priority.
Figure 7c. Annual Accounting Configuration
Configure Annual Accounting
Click Configuration on the top of right hand panel. For option parameters:
- Owner: Users can set owner from Edit » Ownership..., right click resource assessment form the left hand panel and choose Enable Ownership from the drop-down menu. Users can edit details of owner from the owners table. Once ownership system are set up, users can choose any owner from the drop-down menu beside Owner in Figure 7c.
- Debit Type: determines how water is deducted from all the accounts based on either order or use
- Start of Water Year: Day-month that the water year starts for the system.
- Usage to Date: represents how much of the water allocated has been ordered or used by water users in the water year to date. There are two options for usage to date - usage from function and usage from account host. When losses need to be considered, an expression may be required to account for this.
The storage window lists all the water storage in the project. Users can tick any storage type they want to run in this project.
The Inflow window lists all the inflow in the project. Users can also tick any inflow they want to run in this project. The recession factor of each inflow can be edited by a constant or a function manager.
Users can also set Other Resources and Commitments by click the line under the Name of these two windows and a constant value or a function will also be available for editing the resources or commitments that added.
Accounts Summary
Accounts can be managed at Annual Accounting or Account Type levels.
Allocation
Click Allocation beside accounts on the top of right hand panel, Available Resource Versus Allocation displays below (Figure ?). The appearance of Allocation depends on the choice of method to apply for this account type in ARA table in configuration of Account Type, The ARA table will display as the variations below (Figure ?).
- If function was chose in Method to apply for this account type in ARA table before, the Resource in the table will calculate automatically based on the function that was set at the Account or Account Type level
- If Monthly Varying was chose in Method to apply for this account type in ARA table before, users need to set the date for resource calculations. The calculation method was already chosen at an Account Type level, either interpolate or thresholds. Click the number below the Account Type name, the monthly varying window will display as in Figure ??. Users can set resource of each monthly manually or by import or export data from the Import and Export button below. If interpolate is chosen for calculation method, the Resource of the first column will calculated automatically based on current and next month values. More details about interpolate can be found in SRG. If threshold is chosen, Resource of the first column will get value automatically form current month.
- If Percent (with Function) was chose in Method to apply for this account type in ARA table before, “Function” below the account type is editable because functions of this method cannot be set at a lower level.
- If Percent (with linked volume) was chose in Method to apply for this account type in ARA table before, the account type has a unit of (%) and the account type column can be editable by typing number directly to the table. Then the Resource column will calculated automatically based on account shares times percentage.
- If Volumetric was chose in Method to apply for this account type in ARA table before, the account type has a unit of (ML) and the rural column can be editable by typing number directly to the table. Then the value in Resource column is equal to that in Account Type column.
Figure ? Allocation summary
Figure ?? Monthly Varying Allcoation Window
Trigger Priority
Click Trigger Priority on the top of right hand panel, the trigger priority page is shown as Figure ???. The triggers will be separated into two types based on “timestep begining” and “timestep End”. For each type or triggers, users can choose the trigger and move it up or down to set the priority for this trigger.
Figure ??? Trigger Priority screen
Continuous Sharing Resource Assessment
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 ;
- 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) | ||
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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.
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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:
Continuous Accounting
A Continuous Accounting resource assessment system can be created in Source to replicate the Resource assessment system used in the Gwydir and Namoi in NSW. There are a number of defining features of a continuous accounting system which differentiate it from continuous sharing and annual allocation systems:
- Assessments of whether a new allocation can be made occur intermittently (based on triggers defined within the plan) with a new allocation resulting in an additional volume of water added to user’s accounts. With continuous accounting, there is no end of year forfeiture of allocation. There are, however, limits on the volume that can be held in a general security account at any one time and usage limits may also apply;
- An account is maintained for the system as a whole to meet transmission and operation losses (TOL) for delivery of regulated water. An accounting process is followed to determine whether any of the available storage volume is unallocated. The unallocated volume remains after the following have been deducted from the active storage volume:
- reserve required for storage losses;
- reserve required for high security uses including an allowance for transmission losses to deliver these supplies;
- existing volume allocated to the generic system share/s;
- existing volumes allocated to general security entitlements in this system; and
- the volume required to be held in the system’s transmission and operation loss account.
- High security accounts are assigned an allocation based on a defined relationship between percentage of the high security reserve met and allocation to accounts. The reserve set aside for high security uses is generally greater than the volume that is allocated to the high security accounts. Whilst the full reserve volume is set aside at each resource assessment prior to making an additional allocation, the accounts are only assigned an allocation on an annual basis.
The enhancements to continuous accounting in Source over IQQM are:
- Ability to simulate more than one type of resource allocation and accounting method in the one scenario and to link one system to another;
- Ability to specify data to calculate the initial balance of the usage limit;
- Better simulation of management during dry periods including the ability to:
- Restrict allocations to high security accounts during dry periods where the required reserve cannot be met;
- Define the TOL factor as a variable depending on account balances. This allows a higher factor to be defined when balances are low, as a higher proportion of the allocations will be required to cover transmission losses; and
- Represent the rules which may reduce the required high security reserve.
Adding a continuous accounting system
A Continuous Accounting system can be added to a particular scenario in a project using the Resource Assessment Explorer (). Right click on the scenario and choose Add Continuous Accounting from the contextual menu (Figure 11). The parameters to configure are described in Table 2. Note that the Resource Allocation Table defines the allocation priority when there is more than one account type. It also defines the TOL allocations for each eligible system account type.
Figure 11. Continuous accounting (Configuration)
Table 2. Continuous Accounting, Configuration parameters
Item Name | Description |
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Owner | Volume of water available for the Resource Assessment System based on the ownership share of any assigned storages. Ignore for ownership off case. |
Debit Type | Determines how water is deducted from all accounts associated with this continuous accounting system; based on either order or extractions. |
Start of Water Year | Day-month that the water year starts for the continuous accounting system. Relevant for high security accounts as they are treated as annual accounts. The water year is also applicable to usage limits for the general security accounts. |
No further resource assessments from this date | Day-month after which no further resource assessments should be conducted. |
Timesteps per Assessment | Defines number of time-steps between assessments. |
Assigned Storages Table | Lists all storage scenarios. These can be included as resources for the Resource Assessment System if required. |
Account Type | Lists the account types available by default in a continuous accounting system. |
Allocation Priority | Determines the order in which account types will be credited during a resource allocation. |
TOL Share (also known as the TOL factor) | Proportion of allocations which are to be held in reserve for the transmission and operation loss (TOL) account. You can enter either a fixed or variable value via a lookup table (click on the linked TOL value and choose Linear TOL share). This table relates the total volume in accounts for that account type to the TOL factor. It uses interpolation between entries, but does not extrapolate beyond the last one. |
TOL Minshare | Defines minimum TOL account as a proportion of unused entitlement that must be maintained. If this minimum cannot be met, temporary borrowing from the general security accounts occurs to achieve the required minshare. |
When you add a continuous accounting system, the following account types are automatically loaded:
- Storage Loss Reserve - define the reserve required for evaporation and seepage losses from storage;
- High Security Group 1 - define the reserve required for high security users. Also allows you to define accounts which relate to this reserve and the method for allocating water to these accounts;
- High Security Group 2 - same as for High Security Group 1 but relates to a separate, lower priority group of high security users;
- Generic System Share 1 - used to allocate water to another Resource assessment system; and
- General Security 1 - allows you to define accounting rules and shares for general security accounts.
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| Note: IQQM includes a number of inbuilt triggers which are not replicated in Source. For this reason, the Timesteps per assessment parameter may need to be set to 1. Additionally, to replicate IQQM, the TOL Share parameter on the high security account type should be zero. |
Accounts
The Accounts tab (Figure 12) provides a summary of accounts which have been added to the High Security and General Security account types. Additional water user account information is also displayed for each General and High Security Account type. A description of the parameters in this tab are provided in Table 3.
Figure 12. Continuous Accounting (Accounts)
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| Note: In IQQM, No. of shares is named Licence Volume. Additionally, the Initial balance and Previous Usage parameters are not available. |
Table 3. Continuous Accounting, Accounts parameters
Item Name | Description |
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WU Name | Name of the water user - additional water users can be added using Add Account (Figure 13). |
Config | A read only field showing the type of demand model defined for the water user. |
Type | A read only field displaying the account type. |
No. of Shares | Defines the entitlement of the water user in terms of number of shares in the system. |
Initial balance | Initial account balance. If you are going to use the initial account function, you need to ensure that there is sufficient water in storages to cover the total initial balances as well as the required reserves and TOL balance. If the initial balances are set too high a warning message will be generated and the results may not follow the required logic. |
Previous Usage | Indicates if previous usage data has been loaded for the Water User Account. A time series file can be used. |
Storage Loss Reserve
The storage loss reserve (Figure 11) is a volume which is required to account for expected evaporation and seepage losses from the storage. The reserve is debited from the available resource prior to making any other allocations. It may be made a function of the current storage volume or area, which can be specified using an expression. A minimum percentage of the required reserve that must be maintained can also be specified; restrictions are applied to general security accounts (or lowest priority account type) to achieve the required minimum reserve.
Figure 11. Continuous Accounting (Storage loss reserve)
The following parameters must also be specified:
- Minimum to cover storage losses - Defines the percentage of required reserve below which borrowing occurs. This parameter is not available in IQQM, so it must be set to zero; and
- Storage Loss Reserve Requirement - the reserve required to cover storage evaporation and seepage losses. Note that in IQQM, this requirement is defined through the number of months that evaporation is take into account. In some cases the storage loss is combined into the carryover reserve.
High Security Groups
High Security Groups (Figure 12) define the reserve which is required for high security users (may also be referred to as essential supplies). The high security reserve requirement may be defined using two groups - a higher and lower priority group. In the case where only one group is required, you can delete the other by right clicking on the item and choosing Delete. Additional groups may also be added (right click on the Continuous Accounting system and choose the desired system to be added). This can be specified as a fixed value or as an expression. The latter can be used where there are rules that vary the high security reserve requirement.
Figure 12. Continuous Accounting (High Security Group)
High Security accounts are treated as annual accounts with no carryover. In other words, at the start of a water year (as defined at the system level page), all accounts have their existing balance deleted and a new allocation is made. Allocation to high security accounts can be defined using a time series file or simulated based on whether or not the reserve requirement has been met. The Allocation Rules table allows you to define restrictions on allocations to high security accounts if the reserve requirement has not been completely met. The high security shares held by each water user is defined in Accounts. For example, if 1ML is the total reserve, and only 20% of the required high security reserve has been met, then high security accounts will only be given 0.3ML per entitlement share. Table 4 describes the parameters that must be specified.
Table 4. Continuous Accounting, High Security Groups parameters
Item Name | Description |
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High Security Reserve Requirement | Defines the required reserve. May be an expression. |
Required Reserve Below Which Borrowing Occurs | The percentage of required reserve below which borrowing occurs from general security accounts. |
Time series allocation to accounts | If selected, the Allocation to accounts field is enabled, which allows you to define the allocation using an expression. |
Simulate Allocations to accounts | Enables the Using Account Rules table. Account allocations are automatically calculated. |
Using Account Rules | Choosing Interpolate results in the allocation rate being determined based on interpolation between the specified rows. If you choose Thresholds, HS Reserve Met in the allocation table is treated as a threshold that has to be exceeded for the allocation rate to apply. |
HS reserve met | Defines the High Security reserve balance as a percentage of the High Security Reserve requirement. |
HS Allocation | Defines the allocation to accounts per share in that High Security group. |
Generic system share
The generic system share (GSS) is used to allocate water to another resource assessment system. Water user accounts cannot be added directly to the GSS account from within the Resource Assessment Explorer. The accounts associated with the GSS are configured as part of the linked system. The GSS is credited as part of the continuous accounting allocation method and is debited when accounts in the linked Resource assessment system are debited. If an allocation is made to the GSS, this volume is distributed to users as part of the resource assessment phase of the linked system. The configuration dialog is shown in Figure 13.
Figure 13. Continuous Accounting (Generic system share)
The following parameters must be specified for a GSS:
- Time Series Allocation - Enables the entry of a function for allocating to the GSS;
- Simulate Allocation - Define an expression to allocate to GSS. The value of the expression is treated as a volume to be added to the GSS account subject to available water limitations; and
- Total Volume Initial Balance - Initial balance in the GSS account.
GSS is generally used with resource assessment system linking to an annual accounting system where a portion of the resource assessment system is determined by the output of another system.
TO BE CHANGED:
In the Resource Assessment Explorer, the Expression Editor dialog allows you to link two resource assessment systems using the Time of Evaluation tab. Normally, fields in the expression editor are lagged by a time-step (that is, they get their value from the last time-step to use in the current time-step). Enabling the During Resource Assessment checkbox results in the resource assessment system linked parameters being executed within the current time-step. As long as the resource assessment system appears above another resource assessment system in the hierarchical list, the values will be up-to-date in the time-step. Conversely, if one resource assessment system appears below a linked resource assessment system, its values will be lagged by a time-step.
General Security
This item (Figure 14) allows you to define accounting rules for accounts. The general security shares held by each water user is defined using the Accounts tab. The parameters that must be specified are described in Table 5. In the example shown in Figure 17, allocations have been defined to general security account should be simulated using the in-built continuous accounting functionality. There has been no restriction set on the minimum or maximum balance volumes. If, for example, there is a maximum balance of 2ML per entitlement share. This means that if a water user has an entitlement of 200 shares, their maximum account balance is 400ML. Two usage limits have been defined. The first says that no more than 1.25 ML can be used per entitlement share in any water year. The second says that no more than 3ML can be used per entitlement share in any 3 consecutive water years. These rules replicate the conditions for the Namoi river system.
Figure 14. Continuous Accounting (General Security)
Table 5. Continuous Accounting, General Security parameters
Item Name | Description |
|---|---|
Time series Allocation | Allows you to define a time series file of volume to be allocated per unit share at that time-step. This volume is added to user’s accounts based on their number of shares. |
Simulate Allocation | Determines the allocations to general security accounts which assess water availability. |
Maximum Balance | Defines the maximum volume of water which can be held in an account. If an allocation results in this limit being exceeded, then the excess amount is redistributed to other accounts. |
Minimum Balance | If a minimum balance is defined, then order or extractions will not be allowed if it will cause the balance to drop below the minimum specified. This is not included in IQQM. |
Usage Limits | |
Period | Time period that the limit applies to - Moving Water Year or Moving Window. |
Quantity | Specify if the limit is Per Unit Share or an Absolute quantity. To replicate IQQM, set this parameter to Per Unit Share. |
Years / Window | For a moving water year, enter the number of years the usage limit applies to. For a moving window, define the number of days that the usage limit applies to. |
Quantity setting | Usage limit over the period that is to be applied to all accounts. |
Ownership and resource assessment
Resource assessment systems are generally used with ownership when one owner has borrowed from a second owner, and payback is required. One method of paying back water can be accomplished through a resource assessment system. Refer to Borrow and Payback Systems, Distribution Systems for further details on configuring this arrangement in Source.