A Gauge node either represents a physical recording device that measures river levels at a point in a river or a logical point in a river model where you can record and view the modelled flow. Gauge nodes are used in conjunction with rating curves to estimate flows for a particular location. You can use a gauge node for model calibration and verification, by comparing observed and predicted flow.
Figure 1. Gauge node
The Bureau of Meteorology (BOM) station identifier can be set from the station list visible in Figure 1. Find and select the station name in the list and click OK.The Use Inbuilt Station checkbox is enabled by default and ensures that an Australian based gauge is used. You can disable this checkbox to use a non-Australian based gauge.If you have a time series for the physical gauge location, you can load it by clicking the file in Data Sources. This populates the chart on the right hand side with the time series. Table 2 shows the file format. However, this data is for your own reference only. It plays no part in the model run.
Table 1. Gauge node (data file format)
| Row | Column (comma-separated) | |
|---|---|---|
| 1 | 2 | |
| 1 | date | value |
Rating Curves
A rating curve converts a flow into a level, producing an output of level. You would often have recorded gauge level at a gauge rather than flow, thus making it useful for calibration.
Observed flow
This is where you input observed flow by entering a value, supplying a time series or defining a function (Figure 2).
| Anchor | ||||
|---|---|---|---|---|
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Enabling the Set Flow checkbox results in the modelled flow at a gauge being overridden by the observed flow and changes the gauge node icon (Figure 3). This is used in operations environments to check for unaccounted differences in water balances on links. Refer to Forecasting for details.
Figure 2. Gauge node, Observed flow
Figure 3. Gauge node, observed data replaces modelled data
Ownership
This menu item is available when ownership has been enabled (using Edit» Ownership), and allows you to configure ownership for the gauge node. Refer to Ownership for more information.
Forecast unaccounted difference
This is similar to the recession forecast model in the inflow node. Refer to Forecasting inflows.
Constituents
This behaves in a similar manner as Gauge flow. Refer to Constituents - Gauge. Ensure that constituents and constituent sources have been defined prior to configuring them are defined (using Edit » Constituents) before configuring them at the gauge node.