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Description

Th PERFECT GWLag plugin allows you to model groundwater and its interactions in a sub-catchment. Ensure that the following file has been loaded into the Plugin manager prior to creating a new GWLag project: 

RiverSystem.Plugins.PerfectGWLag.dll

Once the plugin has been loaded, using the Geographic Wizard, 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. Geographic Wizard, Network definition (GW-Lag)

 

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). Define the functional units using a shape file and assign areas to them using a raster (Figure 3).

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

 

 

Figure 3. Geographic Wizard, 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 the options in the Edit menu (refer to Rainfall runoff models for details):

  • Constituent generation – As an example, you can add “Salt” as a constituent and assign the “Simple GW salt model”;
  • Rainfall runoff – assign “PERFECT GWLag” as a model. To assign inputs, choose PERFECT GWLag model input assignment from the Available Methods drop down menu (Figure 2) and load the weather database you wish to use. Also check the following:
    • The station number from each FU (left hand column) matches the station numbers on the right hand side (drop down lists, right hand columns). If they do not, the entry on the right hand side will be the closest text based match, not the closest geographic match. You can adjust the matches by selecting an alternate station from the drop down list of stations available in the loaded weather database;
    • Note that the minimum and maximum dates will be displayed by default. To save memory you can either import the desired time period or import the entire range but run the model for a selected period. The latter is a more flexible option.
  • Filter – Assign any filter model you wish from the drop down menu;
  • Links – you can add a model to selected links and if flow routing or a storage model is required. Note that there is no link model specific to the Groundwater tools in Source; and
  • Nodes – select FlowScaledLossModel from the Node models drop down list and click Add Model.
Figure 2. Geographic Wizard - 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.

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):

  • Select the Landuse tab under Perfect Parameters and click Load. Import the land use database in the same way;
  • Once the database is loaded, check and adjust the crop and soil parameter associations. You may also choose to set the initial conditions such as “Proportion of Field Capacity” or “Crop Residue”.
  • Select the Soil tab under Perfect Parameters and click Load. Repeat the process for land use by loading a soils database for specifying soil association groups.
Figure 3. Parameterise Rainfall runoff model – PERFECT

GWLag

To parameterise the GW Lag components, click on the Lag GW parameters tab (shown in Figure 4):

  • Set all the global parameters; these can either be changed individually or all at once. To set individually click on the appropriate cell and type a new value. To make changes to all values in a column (eg. one parameter) change one cell to the desired value. Next, right-click in a cell either above or below (in the same column) and select Apply to all sub-catchments from the contextual menu;
  • Specify the groundwater parameters by importing them from a GFS shape file. Click Load in the Ground Flow System parameters group box and load a GFS shape file;
  • Match the fields for aquifer thickness, hydraulic conductivity and storativity from the loaded GFS shape file by selecting the appropriate field name from each of the three drop-down lists; and
  • Click Apply.
Figure 4. Lag GW Parameters


Constituent Generation

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

  • Specify the through flow salinity percentage value using the up/down arrows;
  • Specify rainfall salinity by loading a rainfall salinity raster, or enter a single value;
  • Enter the averaged aquifer salinity by loading a GFS shape file in the Groundwater Flow System parameters group box; and
  • Choose the field name that represents aquifer salinity using the drop down menu and click Apply.
Figure 5. GWLag Constituent Generation

Node

Select the node from the list of node models and click Configure. The resulting window (Figure 6) shows the parameters that can be changed.

Figure 6. GWLag (Parameterise node model)

Groundwater Pumping

You can also attach catchment scale models to the required sub-catchments by clicking on a sub-catchment and selecting Groundwater Pumping Model in the Catchment Models drop down menu. Click Add Model and select the required pumping model. Click Parameterise to open Figure 7.

Figure 7. GWLag (Parameterise groundwater pumping)

To parameterise the groundwater pumping model, you need to have at least one pump. This can be done either manually or by importing a shape file. To add one manually, ensure that AddSingle is present in the Add Method drop down menu and click Add. The properties for the new pump will be displayed below. Any properties that appear in bold text (such as Name) can be changed. Clicking on these will result in an ellipsis appearing, which must be clicked to make changes.

If you have more than one pump added you can switch between them by selecting the desired pump under Pumps on the top left hand side. When first added, each new pump will have a default value for DistanceProperties, which can be set by clicking on PumpingRiverImpact.

The default values for distance are:

  • DistanceToImpactLocal: The distance between the sub-catchment centroid and the outlet;
  • DistanceToImpactRegional: The distance between the sub-catchment centroid and the scenario outlet, ie the outlet of the most downstream sub-catchment in the scenario;

A new dialog will appear that allows you to change either the local or regional impact distance. To enter a new value for either click in the NumericUpdown box and change the current value to the desired one. When finished click Apply.

By default, no values are set for the gfsproperties (aquifer thickness, storativity, and hydraulic conductivity). When set, these groundwater properties are used to set the diffusivity of the aquifer that the pump is installed in;

gfsProperties can be set by clicking on the property value PumpingRiverImpact.gfsProperties which is highlighted in bold text. On clicking, an elipsis button will appear. Click on this to set the properties (Figure 8);

In the next dialog, set the value for each property manually, or estimate them using a GFS shape file (Figure). To adjust the GFS properties manually, use the up and down arrows to the right of the field and click Apply. To set the properties using a GFS shape file, click Load and select a GFS shape file;

Next click on each of the three combo-boxes and match the field name from the shape file to the GFS property name next to the combo-box (Aquifer thickness, Hydraulic conductivity, Storativity (Figure 35) and click Import and then Apply;

Each pump can have one or more Pumping Instance, which is a period of extraction at a certain rate. By default, a single Pumping Instance is added for each new pump. Pumping Instances appear on the right hand side of the form in the in the “Pumping Instance” group box. To view and set the properties of a pumping instance, click on it in the list box on the top right hand side. You can set any properties in bold. Valid values for StartDate, EndDate, PumpingRate, and RegionalImpact should be set by clicking on the property name which is highlighted in bold, resulting in an elipsis button appearing. Set RegionalImpact to true if the impact is to be applied at the end of catchment and left as false in all other cases.

Additional PumpingInstances can be added by clicking on Add to the right of the PumpingInstance list box (Figure). Likewise, existing ones can also be removed by clicking Remove.

Once the pumping configuration has been completed, click Apply.

Any of the added rainfall runoff, constituent generation or filter model parameters can be changed through the Edit menu.

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