A monthly-pattern demand node allows you to specify a demand as monthly values in megalitres. This is a simple representation supporting the needs of demand and supply analysis. The demand from nodes is accumulated in a bottom-up pass to the identified supply storage, from which water is released (if possible) at the appropriate time to meet the demand. You can configure the model by right-clicking Demand Models and choosing Monthly Pattern from the contextual menu (Figure 1).

Demand can be specified as either:

Monthly values in the Order per month fields when Annual Total checkbox is not ticked and the column of Order Per Mon in Figure1 will be active; or
As a percentage of a total amount. Enable the Use Annual Total checkbox and specify the total demand in the respective field. You can then specify what percentage and share of this total amount to allocate each month.

The demands from the two above methods are independent.

You can enter monthly demand values directly or load the data from a comma-separated (.CSV) file (format shown in Table 1). For simulation over smaller time-steps, the monthly volume is evenly distributed across the time-steps for that month.

Note that the order value and percentage value in Table 1 are not related to each other. Source outputs both values in the system to the CSV file regardless the current option (i.e., Order per month or Percentage of Annual Total), and inputs both values in the CSV file to the system as well. However, Source allows importing a single parameter from the CSV file to the system based on the parameter title (i.e. Value or Proportion) if the CSV file only includes one parameter and another parameter in the system will be set up as zero.

Note: For a monthly pattern demand model, orders are in units of ML, and are averaged over an entire month for a daily value. To ensure that there is no discrepancy in orders between leap and non-leap years, define a time series demand model with a function as the input data source. Refer to the Time Series Demand model for more information.

Refer to Return flows for configuring Return flows in the model.

Figure 1. Water User node (Monthly Pattern, Demand)

Table 1. Water User node (Monthly Pattern, data file format)

Row	Column (comma-separated)
Row	1	2	3
1	Month	Value	Proportion
2	month	order	percentage

Where:

month is the first three characters of the month name with a leading capital letter (eg "Jan")

order is the order in megalitres for the corresponding month.

percentage is the percentage of Annual Total value (%) for the corresponding month. It is only related to the Annual Total (ML).

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