Annual accounting is a custom assessment method for regulated water in the resource assessment module. The related water user, bulk licensing or environmental demand nodes must be configured consistently with the resource assessment system. The general principles for an annual accounting system are:

Available resource is calculated during a defined water year;
Allocation of the resource is made to different account types;
Each account type’s allocation is distributed between accounts linked to this account type; and
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 set up in Source follows these principles.

To set up an Annual Accounting System:

Add annual accounting.
Add and configure:
- Account types to group together accounts that are governed by the same set of rules (such as usage limits), or have the same priority of access to water. See Account types.
- Accounts to each account type to represent water users within that account type. See Accounts.
You may also add and configure:
- Triggers are used to initiate or cancel certain actions in a resource assessment system. These can be added to an annual accounting system, an account type or an account. See Triggers.
- Usage Limits restrict usage by absolute volume or proportion of entitlement, and can cover a water year or movable time window. These can be added to account types or accounts. See Usage limits.
- Off Allocation System to share surplus flows to users. These can be added to an annual accounting system. See Add an off-allocation system.
Configure the global parameters for the Annual Accounting system, including the allocation of resources to accounts and trigger priority. See Annual accounting system configuration.

You add components to an annual accounting system using the tree menu and corresponding context menus (See Managing an annual accounting system). To configure a component, select it from the tree menu and use the display on the right-hand side. How to configure each component is described in the following sections.

Add annual accounting

Create an annual accounting system as follows:

Choose Edit » Resource Assessment... to open the Resource Assessment Explorer; and
Right click Resource Assessment and choose Add Annual Accounting.

Managing an annual accounting system

The tree menu on the left-hand side of the Resource Assessment Explorer (Figure 1) allows you to view all components in your resource assessment system, including any continuous accounting or continuous sharing systems.

In addition to standard functionality (eg. Rename, Delete), you can also do the following from the appropriate context menus (Figure 1):

Add a new off allocation system, account type, account, trigger or usage limit by selecting and right-clicking the parent of the new component.
Duplicate the selected component;
Add Note to the selected component to enter a text-based message, or note, to be associated with the component. Refer to About notes for more information.

By default, components of the same type are listed in the order in which they were created, you can rearrange their order by clicking and dragging an item up or down. This allows you to group items logically, eg. group accounts by location, or triggers by purpose. Note that the order of components is to aid organisation, it has no effect on the resource assessment system.

Figure 1. Annual Accounting, Tree menu

Add an off-allocation system

Off-Allocation systems are assigned to the annual accounting system at the top Annual Accounting level. To add an off-allocation system, right click the annual accounting system (eg Annual Accounting 1, Figure 1) and choose Add Off-Allocation System. Refer to the Off Allocation node for information on how to configure the off-allocation system.

Account types

An annual accounting system may contain several account types (as defined by you). Each account type groups together accounts that are governed by the same set of rules (such as usage limits), or have the same priority of access to water.

To add an account type, right click on the annual accounting system and choose Add Account Type. Once defined, account types can be re-arranged in the tree by dragging and dropping to the required order. This will affect the control execution order and the ARA table column placement.

In the Account Type pane, you can use the:

Configuration tab to configure the account type (shown in Figure 2);
Accounts tab to view a summary of all accounts in the account type;
Carryover tab to configure carryover; and
Non-Debit Accounts tab to view and configure all non-debit accounts in the account type.

The next sections describe each of the tabs.

Account type configuration

Figure 2 shows the configuration parameters required for an account type. These are explained further in Table 1.

Figure 2. Annual accounting, Account type, Configuration

Table 1. Annual Accounting, Account Type, Configuration

Item	Description
Debit Type	Determines how water is deducted from all accounts associated with this annual accounting system; based on either order or extractions.
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 for each account within the account type. Choose: Absolute Volume – specify a volume in the minimum field; Proportion of Entitlement – specify a percentage or proportion; or Unrestricted – the minimum volume is not defined. Extractions will continue even when there is no account balance.
Maximum Balance	Defines the maximum volume of water that can be allocated to an account as part of the allocation process for that account type. If an allocation results in this limit being exceeded, then the excess amount is available to other account types. Options are as for Minimum Balance. If you select Unrestricted, extraction will continue regardless of the account balance.
Allocation Calculation	There are two methods available for calculating allocation: Available Resource Allocation Table – choose to allocate resources using the available resource allocation table (ARA table), which is on the Allocations tab of the annual accounting system (Figure 10). This is the default option. When selected, ARA Table options are displayed, these are explained in Table 2. Function – choose to allocate resources using a function, which you can define by selecting the ellipsis button. A function may reference a wide range of variables available in the model, including allocations to other account types and resource assessment systems.
Allow Decrease	This checkbox controls whether or not an account’s allocation can reduce within the water year.

Note: The Method to apply for this account type in ARA table drop-down menu has several options available (as shown in Figure 2), each with a different set of input parameters, explained in Table 2. The option chosen here affects the view in the Allocation tab for the annual accounting system (Figure 10), and are described in Table 9. See Allocation.

Table 2. Input parameters for the ARA Table options.

Method	Input parameters
Function	Enter a function using the Function Editor.
Monthly varying	Choose the appropriate Calculation Method - either Interpolate or Threshold.
Percent (with function)	Configure the following parameters: Announced Increment checkbox and corresponding field - the proportion of available resource that will be allocated in a block to the account type; Maximum Announced Percent checkbox and corresponding field; Derive 100% Allocation Volume from Accounts checkbox - if enabled, the account type’s share volume is derived from its accounts; and Specify 100% Allocation Volume - The total number of shares allocated. This is enabled only when Derive 100% Allocation Volume from Accounts is disabled.
Percent (with linked volume) - default	Same parameters as Percent (with function).
Volumetric	Volume.

Accounts

Choose the Accounts tab to view a summary of the account host, entitlement and initial balance for all accounts within the selected account type. These parameters are summarised in Table 5 (see Account Configuration). A similar table containing a summary of accounts in all account types, is visible in the Accounts tab for the annual accounting system (see Figure II).

Carryover

This tab allows you to configure several parameters related to carryover, such as spill and its associated parameters (Figure 3). Spill is water released in excess of the downstream requirements. Table 3 explains the configuration parameters.

Figure 3. Annual accounting, Account type, Carryover

Table 3. Annual accounting, Carryover parameters

Item	Description
Max Carryover	This is the maximum amount of water that can be carried over. It can be defined in terms of: Absolute volume – Define a specific number for Max Amount, which means carryover water is limited to that number for each account of this account type; Proportion of Entitlement – Specify a percentage or proportion in Max Amount. In this case, carryover water is limited to a percentage of entitlement for each account of this account type; or Unrestricted – in this case, there is no limit specified.
Maximum Effective Allocation	The maximum amount of water that an account can hold, including allocation and carryover. If enabled, you must define effective allocation in the Limit field. For example, if you specify 130%, allocation plus carryover water cannot exceed 130% of the entitlement. The carryover water will be reduced to prevent allocation plus carryover from exceeding 130% of entitlement. If carryover account does not have enough water to bring maximum effective allocation down to the cap (caused by usage of carryover water etc.), then allocation account will be reduced.
Carryover Rules Changing Over Time	This allows carryover rules to be able to change over time. For example, it can be defined as: from 01/07/2000 to 30/06/2006, carry over is spillable; from 01/07/2006, carry over is non-spillable.
Carryover Type	Select the type of carryover to configure using the drop-down menu: Spillable – You can specify the other spill parameters; or Non-spillable – in this case, spillable water will be 0.
Do Not Carry Over Spillable Water	If enabled, spillable water will not be available for carryover. If disabled, any remaining spillable water will be carried over to the next water year.
Spillable Volume Calculation Method	Spillable water is calculated using one of two methods: Total water - 100%: The calculation is made based on the state of the Water Available While Spillable checkbox: If enabled, Spillable water = max(0, Total allocation water year + Carryover start of water year − 100% entitlement − Total spill reduction water year − Total usage from carryover water year); or If disabled, Spillable water = max(0, Total allocation water year + Carryover start of water year − 100% entitlement − Total spill reduction water year). In this case, spillable water increases with allocation. Carryover - Use: In this case, Spillable water = Carryover start of water year − Total usage carryover water year − Total spill reduction water year.
Spillable	Allows you to trigger the account to spill. You can specify a boolean function to switch account spilling on or off.
Basis of Spilling	There are three options available: Emptied on Spill or Pre-Release – If a spill or pre-release occurs, the spillable water is completely emptied; or Equalise Spillable Carryover Proportions – First, spill is deducted from the account with the greatest carryover as a percent of its entitlement. When the carryover as a percentage of entitlement of the first account reaches that of another account, spill from both pro-rata until the next account is reached, and so on. Reduce pro-rata – Spill is deducted from all other spillable water accounts pro-rata according to volumes in the spillable water accounts. If different account types under the same spill source have the same priority, then the priority of spilling from account types with Emptied on Spill or Pre-Release first, followed by Equalise Spillable Carryover Proportions and Reduce pro-rata last.
Water Available While Spillable	If enabled, Available water = Account balance + Carryover Water. If disabled, Available water = Account balance + Carryover Water − Spillable water.
Spill Reduction Priority	The priority of spill from the carryover account. The default value is 1, which is the highest priority. 2 is the next highest priority, then 3 and so on. During a spill, all accounts of the same priority are grouped together and the spill volume is distributed among these accounts pro rata. Any remaining spill is then passed along to the next priority grouping.
Use Account Type Spill Volume	When enabled, allows you to specify a value for Account Type Spill Volume. This volume will be used instead of the *Spill Volume* set at the top Annual Accounting System level (set on the Configuration tab, see Table 7.)

Non-debit accounts (for NSW)

This tab allows you to work with non-debit accounts. First enable the Enable Non-Debit Accounts checkbox, which allows you to edit the remaining parameters (Figure 4). Parameters are explained in Table 4.

Figure 4. Annual accounting, Account type, Non-Debit Accounts

Table 4. Annual accounting, Account type, Non-Debit Accounts

Item	Description
Enable Non-Debit Accounts	Toggle on to edit the other parameters in this tab except for Per Share Upper Limit.
Use Per Share Upper Limit	Enable to enter value into Per Share Upper Limit, which defines the maximum amount of non-debit water that may be used. The smaller of the Repayment Threshold and the Per Share Upper Limit will be used.
Availability Threshold	The allocation level at which the water user gets access to the account.
Repayment Threshold	The allocation level at which repayments need to be made. As the water user approaches its maximum allocation, repayments need to be made.
Carryover Discount	A discount implemented on the water that is carried over to the following water year. Note that this applies only when Murrumbidgee is chosen as the Balance Calculation Method.
Balance Calculation Method	Choose either Murray, Murrumbidgee or Belubula. This determines which set of rules to use. Upper Namoi is modelled by selecting the Murrumbidgee rules and enabling the Use Per Share Upper Limit.

Accounts

Accounts allow a water user to request resources. They specify the entitlement that a particular water user has for that particular account type. The entitlement is used to apportion the available water between the accounts when new water allocations are made.

Adding an account

In Source, accounts are grouped together under account types, so to add an account, you first to need to add an account type. Right-click on the annual accounting system menu item and choose Add Account Type. Then, there are three ways to add an account:

Right-click on an account type in the tree menu, choose Add Account from the contextual menu.
Select an account type, choose the Accounts tab, and then select Add Account. This will open the Add New Account dialog (similar to that in Figure 5) where you can assign the accounts' host, entitlement and initial balance (defined in Table 5). Click OK.
Select the annual accounting system, choose the Accounts tab, and then select Add Account. This will the Add New Account dialog (Figure 5) where you can assign the accounts' type, host, entitlement and initial balance (defined in Table 5). Click OK.

Figure 5. Annual accounting system, Accounts tab, Add New Account

Account configuration

Regardless of which method you use to add an account, to further configure or edit the account, select it from the tree menu, where it will be listed underneath its account type (Figure 6) These parameters are described in Table 5. Note that Entitlement and Initial Balance can also be edited on the Accounts tab of either the account type or annual accounting system.

Entitlement applies to the account regardless of the start date, but all other parameters on this tab only have effect when the model run commences on a date other than the first day of the water year. If a simulation is started part way through the water year the initial values in the Initial Values at Start of Run group box will apply. Carryover Scalar and Carryover at Start of Water Year are assumed values at the start of the water year that the run commences and do not change within the water year.

Figure 6. Annual accounting, Account type, Add account

Table 5. Annual accounting, Account type, Account parameters

Item	Description
Entitlement	Entitlement volume assigned to the account.
Allocation	Allocation on the first day of the model run.
Account Balance	As its name suggests, this is the initial account balance of the system (corresponds to Initial Balance in Figure 5 and Figure 9). If you enter an initial balance, ensure that there is sufficient water in storages to cover the total initial balances as well as the required reserves. Note that if the initial balances are set too high a warning message will be generated and the results may not follow the required logic.
Carryover Scalar	Used to reduce the carryover commitment when there is not enough resource available in the system. The product of the carryover scalar and carryover start of water year is the carryover commitment at the start of the model run for the account. The carryover scalar is reset to a value between 0 and 1 at the beginning of each water year, depending on the available resource, and increased as resources allow the commitment to be met (in accordance with the ARA table).
Carryover Start of Water Year	The amount of water carried over from the water year prior to the water year that the run commences in.
Previous Usage	The amount of usage between the start of the water year that the run commences in, and the first day of the model run.
Previous Spill from Carryover	The amount of spill reduction from the carryover account between the start of the water year that the run commences in, and the first day of the model run. This is zero if the model run commences on the first day of the water year.
Associated Account Host	This lists all available account hosts in the model (corresponds to Account Host in Figure 5 and Figure 9). An account host can be water user, bulk licensing or environmental demand node. To associate an account host with this account select it from the list. A host can only be associated with one account per account type, so a host that already has an associated account will not appear in the list. Once these have been configured, this association is reflected in the host node's feature editor, which can be used to configure the distribution between associated accounts and carryovers, as follows: For water user nodes, use the Account Sharing table of the Distribution menu item. Refer to Water user node - Demand distribution for details on configuring account sharing in the water user node. For the bulk licensing nodes, use the Accounts Distribution table, see Bulk Licensing Node - Specifying a portfolio of accounts. For environmental demands, use the Portfolios tab of the Environmental Flow Manager.

Note: Each account can have only one host associated with it. Each host can only have one associated account per account type.

Triggers

Triggers specify events that affect the behaviour of the annual accounting system, such as allowing you to reassess accounts during the water year. Triggers can be added to an annual accounting system, an account type or an account. To add a trigger, right-click on the component and choose Add Trigger. This will create the trigger and display the dialog where you can define and configure it, see Types of triggers. Once you have created triggers, you can configure their priority using the Trigger Priority tab for the annual accounting system, see Trigger Priority.

Usage limit

Accounts and account types may have limitations placed on their usage that are independent of their allocation (or account balance). This dichotomy may occur because the allocation relates to a water year, and the usage limitation relates to multiple years or a moving time period.

Usage limits can be added to an account type or an account. To add a usage limit, right-click on the component and choose Add usage limit, then configure the usage limit using the dialog (Figure 7, Table 6). An account can have several usage limits, each can be designed to initiate a particular limit.

Figure 7. Annual Accounting, Usage limit

Table 6. Annual Accounting, Usage limit parameters

Item	Description
Period	Time period that the limit applies to - *Moving Water Year, Moving Window* or *Water Year. Moving water year is very similar to moving window but is based on a succession of water year. For example, if usage limits relates to 2 successive water years, choose Moving Water Year* and set Years to 2. If a usage limits relates to a single water year, choose *Moving Water Year* and set Years to 1. Where a "rolling years" usage limit has been defined in IQQM for general security accounts, these should be defined as Moving Water Year limits in Source.
Quantity	Specify if the limit is Proportion of Entitlement or an Absolute Volume. To replicate IQQM, set this parameter to Proportion of Entitlement.
Years	For a moving water year, enter the number of years the usage limit applies to. For a moving window, define the number and time units (eg. days) that the usage limit applies to.
Quantity	Usage limit over the period that is to be applied to all accounts, as either Proportion of Entitlement or Absolute Volume.

Annual accounting system configuration

As shown in Figure 8, you can do the following at the top Annual Accounting level:

Configure annual accounting using the Configuration tab;
View summary information of all accounts added with the Accounts tab;
Set the available resource vs allocation (ARA) table using the Allocation tab; and
Set trigger priority with the Trigger Priority tab.

The next sections provide further details of all the tabs listed above.

Configuration

This tab provides an overview of the annual accounting system (Figure 8); configuration parameters are explained in Table 7.

Figure 8. Annual Accounting, Configuration

Table 7. Annual accounting, Configuration tab

Item	Description
Start of Water Year	Day-month that the water year starts. If unspecified, it defaults to 1st July.
Owner	This lists all the owners that have been configured using the Ownership Setup dialog (refer to Ownership in Source).
Usage to date	Determines how much of the water allocated has been ordered or used by water users in the water year to date. There are three options available: Usage From Account Host – calculates usage from the associated account host(s) (Water User, Bulk Licensing or Environmental Demand) - this is the default option. Usage from Account Host & Distribution Losses – calculates usage from the associated account host(s) and the distribution loss at any connected supply point(s) (see Supply Point - Distribution Loss), and; *Usage from Function* – a function may be entered for Usage Amount when neither of the other two options is sufficient, for example, when losses upstream of the water user need to be considered.
Spill Volume	In cases where the available water is in excess of the volume ordered by entitlement holders, the extra volume is referred to as Spill Volume. This is usually defined as a function.
Usage Amount	Only applicable when Usage to date is assigned Usage from Function, enter a function or value for the usage amount.
Storages	Lists all the storages in the scenario. Enable a storage by toggling on the check box to use it as a resource in the annual accounting system. For each enabled storage, you may specify the Evaporation Pattern and Minimum Inflow as a monthly pattern. Note that net evaporation can be negative. At assessment date, the available storage volume is reduced by the net evaporation volume to end of season and may be increased by the inflow volume to end of season (if Use inflow for resource is enabled). These monthly volumes are appropriately proportioned when assessment/end of season dates are not at start/end of month. Enable Use Inflow for Resource to add the sum of the inflows to the end of the water year to the current storage volume. Enable Use Inflow for Evaporation to add the sum of inflows to the end of the water year to the current storage volume before determining surface area to calculate volume of evaporation. If neither Use Inflow for Resource nor Use Inflow for Evaporation is enabled, even if there is a Minimum Inflow monthly pattern defined, it will not be used in calculations.
Inflows	Lists all the inflows in the project. Enable any inflow to use it as a resource for the annual accounting system. The recession factor of each inflow can be set either as a constant value or as a function. Source multiplies the downstream flow volume for the selected inflow node by the recession factor to calculate the volume of water available as a resource.
Other Resources	Represents other resources such as inter-valley transfers. To add another resource, click on the cell under Name and enter a name, then click on Function... under Resources to enter a value or define a function to represent that resource.
Commitments	These are used to represent other commitments such as special reserves or provision for minimum flows. Commitments are added the same way as Other Resources, see above.

Accounts

This tab provides a summary of all the accounts in the annual accounting system in the Accounts table. Its parameters are outlined in Table 5 (see Account Configuration) You can add an account from this tab by selecting add account, see Adding an account and Figure 5. Account Entitlement and Initial Balance can be be set by using a fixed value, data source or function (Figure 9).

Figure 9. Annual Accounting, Accounts tab

Allocation

The Allocation tab contains the available resource vs allocation table (ARA table), which shows the quantity of resources required to achieve the specified allocations, including provision for carryover. Parameters to specify in this dialog are outlined in Table 8.

You can copy cells of the ARA table by selecting the cells so that they are highlighted blue, and then pressing Ctrl+C. You can then paste the contents elsewhere in the ARA table or to another program by pressing Ctrl+V. When you paste the cell contents into another program the name of the column(s) will also bepasted. You can also paste values from an external program into the ARA table.

Figure 10. Annual accounting, Allocation tab

Freezing columns

In the allocation tab you can freeze the columns so the user can scroll right to the multiple account types without losing the ability to compare the columns.

The number of columns that are able to be 'frozen' can be configured from the numeric input to the 'Freeze column' numeric drop down. Also the user can go back to the previous settings with Reset View.

As the user adds new account types this table will still populate the columns with the newly added.

The users can right-click on any desired column and click 'Freeze column' to freeze specific column. The 'frozen' column will move to the left side of the table next to the existing frozen columns.

Table 8. Annual accounting, Allocation parameters

Item	Description
Date of resource calculation	Choose your desired date by clicking on the date-picker.
Show Function Initial values	When enabled, this shows the initial values of functions being used for the account type and is only applicable when *Function* or *Percent (with Function)* is chosen as the preferred option in Method to apply for this account type in ARA table for account type (as shown in Figure 2).
Dump ARA table to desktop each reassessment	When enabled, the ARA table is exported to the local machine's desktop for every re-assessment. It is particularly useful when checking the available resource and allocation after each re-assessment.
Parameters in the ARA table - Configuration of the Resource and Account Type columns depends on which method was chosen for Method to apply for this account type in ARA table, this can be found on the configuration tab for each account type (see Configuring an account type). Table 9 explains how the ARA table varies with this parameter. Table 9 explains how the ARA table varies with this parameter.
Resource	The water available in the system.
Carryover	The proportion of water that is carried over to the next water year.
The remaining columns correspond to the account types in the annual accounting system.

Table 9. Annual accounting, Allocation (Variations)

Menu option in ARA table	Resulting variation in Allocation tab (Annual Accounting)
Percent (with linked volume)	The allocations in the *Account Type* column(s) can be edited directly on the table. The *Resource* column is calculated automatically based on the percentage allocation of the Account Type share volume.
Function	The Resource column is calculated based on the function specified for the Account Type on its configuration tab. To view or edit the function, use the Account Type's configuration tab. Note: You must click OK to save and close the Resource Assessment Explorer for the Resource column to populate.
Monthly-varying	In the Account Type column, click the hyperlink to open the table showing the allocations for each month in the water year. Values in the table will be calculated depending on the option chosen for the calculation method in the Account Type configuration tab. If *Interpolate* is chosen for the calculation method, the *Resource* of the first column is calculated based on the current and next month values. If Threshold is chosen, the value in the *Resource* column corresponds to the value in the current month. You can set the resource for each monthly manually or by importing it. This data can also be exported.
Percent (with function)	In the Account Type column, click Function... to specify what proportion of Shares (in the Account Type) will be assigned to the Resource column. For example, consider Shares = 50000ML, and the function specifies 10% in the Account Type column, the value in the Resource column will be 5000 (10%*50000) ML.
Volumetric	The value is directly editable in the table. The Resource column is then based on the value in the *Account Type* column.

Trigger Priority

Triggers are used to initiate or cancel certain actions for an account and various triggers can be added at different levels in annual accounting. There are several types of triggers - refer to Types of triggers.

Once defined, triggers appear in the Trigger Priority tab (Figure 11) and are separated depending on their time of execution: Timestep Beginning or Timestep End. They can be prioritised by clicking and dragging to the desired location.

Add annual accounting

Managing an annual accounting system

Figure 1. Annual Accounting, Tree menu

Add an off-allocation system

Account types

Account type configuration

Figure 2. Annual accounting, Account type, Configuration

Table 1. Annual Accounting, Account Type, Configuration

Table 2. Input parameters for the ARA Table options.

Accounts

Carryover

Figure 3. Annual accounting, Account type, Carryover

Table 3. Annual accounting, Carryover parameters

Non-debit accounts (for NSW)

Figure 4. Annual accounting, Account type, Non-Debit Accounts

Table 4. Annual accounting, Account type, Non-Debit Accounts

Accounts

Adding an account

Figure 5. Annual accounting system, Accounts tab, Add New Account

Account configuration

Table 5. Annual accounting, Account type, Account parameters

Triggers

Usage limit

Figure 7. Annual Accounting, Usage limit

Table 6. Annual Accounting, Usage limit parameters

Annual accounting system configuration

Configuration

Figure 8. Annual Accounting, Configuration

Table 7. Annual accounting, Configuration tab

Accounts

Figure 9. Annual Accounting, Accounts tab

Allocation

Figure 10. Annual accounting, Allocation tab

Freezing columns

Table 8. Annual accounting, Allocation parameters

Table 9. Annual accounting, Allocation (Variations)

Trigger Priority

Figure 11. Annual accounting, Priority Trigger

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