Note: The process of working with the GWLag plugin outlined on this page is hasn't been updated for Source 3.7.0 and onwards.

eWater acknowledges the NSW Department of Environment for their contribution of the Adelong dataset. This dataset was used in the GWLag plugin to generate examples for the Source User Guide.


The PERFECT GWLag plugin allows you to model groundwater and its interactions in a sub-catchment. 

On loading the plugin, use the Geographic Wizard to first create a standard set of sub-catchments to suit your study area and modelling requirements, then configure the appropriate parameters to model groundwater.

GWLag network definition

In Step 3 of the Geographic wizard, load a DEM-based network and configure the outlets as appropriate (Figure 1).

Figure 1. GW-Lag, Network definition

List constituents and FUs

Next, list any constituents that you want to model (in step 4), followed by the functional units (FUs) in step 5 (Figure 2). It is possible to define the functional units using a shape file and assign areas to them using a raster (Figure 3).

Figure 2. GW-Lag, Name FUs (GW-Lag)


Figure 3. GW-Lag, Assign areas to FUs

Defining and assigning models

You can then assign models to sub-catchments for rainfall runoff, constituent generation, and any filtering you wish using the Geographic Wizard, or later, using the options in the Edit menu (refer to Rainfall runoff models for details):

Figure 4. GW-Lag - Assigning inputs to rainfall runoff models


Parameterising models

This section describes how to parameterise each of the assigned models. It requires the parameterisation of both plugin components – PERFECT and GWLag.

Constituent generation

Choose SimpleGWSaltModel parameterisation from the Available Methods drop down list (Figure 170).

Figure 5. GWLag constituent generation

Rainfall runoff


Choose PERFECT-GWLag model parameterisation from the Available Methods drop down list. The PERFECT and GWLag parameters are specified under separate tabs.

To parameterise PERFECT (as shown in Figure 3):

Figure 6. Parameterise rainfall runoff model – PERFECT


To parameterise the GW Lag components, click on the Lag GW parameters tab (shown in Figure 7):

Figure 7. Lag GW parameters