The Geographic Wizard is a structured sequence of windows that guides you through the process of creating a catchments scenario. On completion of the wizard, you will be presented with a node-link network. Figure 114 shows the sequence of steps in the wizard.

If some data or parameter values are unavailable whilst creating the scenario, skip the step by clicking Next. Once you have created a scenario, you can make changes using the choices on the Edit menu.

In some situations, the wizard will skip over several steps if certain values have not been specified. For example, if you do not define any constituents (step 4), you cannot assign inputs or parameterise any constituent-related steps such as rainfall runoff models or filter models. Therefore, steps 8-13 will appear greyed out in the wizard progress indicator (Figure 115). This figure also shows the action buttons that are visible at the bottom of every screen in the wizard.

On completion of a step, you can move to the next step by clicking Next and backwards by selecting Back. Note that you cannot go back to the network definition step once you have completed it and moved to the next step. Cancel allows you to quit the wizard at any time. Note that you will lose all the data entered so far. You can also complete the scenario if the Finish button is active (from step 7 onwards). Source will create a scenario when all mandatory steps have been completed, even if all the steps in the wizard have not been completed.

Note Most of the windows appearing in the wizard are identical to the related Edit menu choices. For steps that are related to rainfall runoff, constituent generation and filter models and have screen output similar to the wizard, refer to the Constituent generation and filtering models and Rainfall runoff models chapters.

Welcome screen (Step 1)

The Welcome screen gives some information about the steps within the wizard. These include:

• Specifying the catchment network;
• Creating a list of the constituents and functional units that will be used in the scenario;
• Assigning functional unit areas and models to rainfall runoff, constituent generation, filters, node and links;
• Selecting input files for the rainfall runoff models; and
• Setting parameter values for models assigned in the node-link network.

Name the scenario (Step 2)

Enter a scenario name and an appropriate description, or accept the defaults.

Define the network (Step 3)

You must define the sub-catchments and stream network within the catchment, using either a catchment map or Digital Elevation Model (DEM). There are a number of methods for defining the network.

The DEM based network generation method requires a DEM, and divides the entire node-link network into sub-catchments based on a user-specified measure of upstream area (sometimes called stream threshold), usually for first-order streams. You can define points on the stream network where the ends of sub-catchments will be formed. The minimum sub-catchment area can also be modified. For example, in a node-link network spanning 1000 km2, entering a stream threshold of 10 km2 will produce approximately 100 sub-catchments.

DEMs that have been derived only from contour maps or from other remote sensing technologies such as light detection and ranging (LIDAR) or shuttle terrain radar mapping (STRM) are usually not hydrologically correct. Such DEMs need to be adjusted to represent the flow of streams in the right direction. This is because they create a sense that there are spurious pits in the landscape when actually, none are present.

The Draw Network method allows you to define the networks manually, by loading a sub-catchment map (a raster with cell values set according to sub-catchment number) and then connecting sub-catchments by clicking and dragging using the mouse. This specifies how those sub-catchments are linked together by the node-link. You should use this method when you have previously defined the boundaries of your sub-catchments, either by using Source or an external program.

You can create a draft of your sub-catchment boundaries using the DEM based network generation method, export those boundaries from Source, edit them in an external GIS program (for example combining or splitting sub-catchments), and then import your edited sub-catchment boundaries to create a revised sub-catchment node-link network using the Draw Network method.

Note Any spatial layers displayed in the Geographic Editor must have the same projection as the sub-catchment map or DEM that was used to create the node-link network.

To use the DEM-based Network Generation method:

• Choose DEM based network generation from the Available Methods drop-down menu;
• Click Load DEM;
• Navigate to the catchment DEM and open it. Source generates a default network based on a minimum sub-catchment area of 50 km2. It is recommended that you specify the minimum sub-catchment area prior to loading a high resolution DEM to reduce computational time;
• Specify a different minimum sub-catchment area in km2, if necessary, and click Recompute Streams. The drainage density depends on the minimum sub-catchment area; and
• Select a desired catchment outlet (a point in the network where all streams in the desired area converge) for investigation by clicking inside the map. This generates a network area broken into sub-catchments (shaded blue), where two sub-catchments converge at a confluence.

Figure 115 shows an example of a sub-catchment network.

Once a DEM has been loaded, you can alter it by right-clicking and choosing the various options available in the contextual menu:

• To add a new catchment outlet, choose Select Cell from the contextual menu, and select another point on the catchment map; or
• Pan allows you to move the map up, down, left or right; or
• To zoom in, right-click, and choose Zoom In. Drag the mouse to form a zoom box (top right to lower left). To zoom out, double-click anywhere on the map or click Undo Zoom; or
• To remove a catchment outlet point, choose Remove Cell; or
• Choose Properties to change the attributes of various elements, such as the colour of nodes or links; or
• Save allows you to save the map as a .asc file.

You can use a list of nodes to define the sub-catchments as well:

• Set the stream threshold to a large value (so that only a few sub-catchments are defined); and
• Load a list of nodes in one of the pre-defined formats (eg .MIF, .SHP, .tsd). Tarsier site files (TSD) list nodes in order with a UTM grid reference, identifying number and name (Easting, Northing, UTM Zone, [Z (m)], [T] , Value, [Weight], Label).

You can select multiple catchment outlets on a DEM map, which can take a long time when there are many cells in the DEM. You can set Source to recalculate networks manually by enabling Multiple Outlets. Then, select multiple points/cells on the DEM as required and click Generate Network.

Additional tabs under Multiple Outlets allow you to work with outlet nodes:

• Add all outlets - detects all outlet edge cells with the lowest elevation and adds nodes at these points;
• Add largest outlet - detects the largest outlet in a DEM and adds a node for the outlet;
• Import outlets - allows you to import a file of outlet nodes. This is different from Load Node, which creates confluence nodes; and
• Clear outlets - clears all specified outlet nodes.

Note that the total area covered by the catchment can be viewed in the Recording Manager once the scenario has been run (Figure 116).

To use the Draw Network method:

• Choose Draw Network from the Available Methods drop-down menu;
• Click Load Sub-catchment Map and open the desired sub-catchment raster file;
• Click and drag on the map to create a stream network by specifying the direction of flow between sub-catchments. Ensure a connection is also made from the lower-most sub-catchment to a point outside the sub-catchment.This is the catchment outlet, highlighted with a circle in Figure 117.
• Click Next once the network includes every sub-catchment and a corresponding outlet. You can rename the sub-catchments in the table under the Sub-catchment button.

If you need to delete a link, right-click on the map and click Select Link/Node. Click on the link you wish to delete. It will turn red. Press the Delete key on the keyboard or click Delete Selected elements on the right of the map. Ensure that you delete the nodes connecting the links as well. To re-draw links, right-click on the map and choose Draw Network. Continue drawing links as before.

The other options in the list (Pan, Zoom, Copy graph and Properties) have the same function as that described for using the DEM based network generation method.

Additional buttons under Load Sub-catchment Map assist you in adding further detail to the network map. Load Gauge Map and Load Background Maps allow you to upload a shape file of gauges or an image like a stream flow map to assist in drawing the node-link network. Add Links from Shp file allows you to load a shape file of links that is then mapped to the sub-catchment map automatically.

If all the sub-catchments have not been joined and you click Next, an error will appear indicating which sub-catchments have not been connected (Figure 118). The sub-catchments shaded in blue are not connected.

Define constituents (Step 4)

Enter a list of constituents that are of interest and which you wish to model. If you do not enter any constituents, the wizard does not display any steps that are constituent-related ie the constituent generation, filter assignment and filter parameterisation steps appear greyed out. Examples of constituents are total nitrogen (often abbreviated as TN), total suspended sediment (TSS), heat, dissolved oxygen, radioisotope tracers, etc.

Once constituents are added and you have moved to the next step in the wizard, they are fixed in the model for this scenario and cannot be removed. Thus, it is important at this point to add ALL constituents that are likely to be used in the modelling process.

You can also add constituents using Edit > Constituents > Configure... , which opens the Configure Constiuents dialog (#anchor-103-anchor).To add a constituent, type its abbreviation in the Name field and either click Add or press the carriage return. To remove a constituent, highlight it and click Delete.

Specify functional units (Step 5)

You must specify all possible functional units present in the area of interest, or that you want to represent in the scenario. There are three ways of defining FUs: manually, from a text file, or from a shape file (Figure 119).

The default method of defining FUs is manually. To add a FU, type it in the Name field, and either click Add or press carriage return. To remove a FU, highlight it and click Delete.

You can import FU names from a text file by choosing Import from a text file from the Available Methods drop-down menu. The format of the text file is shown in Figure 120.

You can also import FU names from a shape file:

• Choose Specify from a Shapefile from the Available Methods drop-down menu.
• Click Load to upload a shape file that has been configured with a field for FU types.
• Select the layer from the list and click Create. A list of FU names is generated in the right hand pane. The shape file used to define FU types will also be used to assign the areas to each FU in each sub-catchment.

Note that once a scenario is complete it is possible to add or remove FUs. However, the FU areas must be adjusted to incorporate this change. Additionally, rainfall runoff, constituent, filtering models and the corresponding input data must be re-assigned and parameterised.

Specify functional unit areas (Step 6)

You must assign areas to every functional unit in each sub-catchment. The functional units that appear depend on those you defined previously. You can assign areas manually (using either the Table or Map tabs), or from a raster such as a land use map.

To assign FU areas manually using the Table tab:

• Choose Manual Area Allocation from the Available Methods drop-down menu;
• For each sub-catchment, enter the area that is allocated to each FU. You can specify this as an absolute value in the Area (ha) column, or as a percentage in the Area (%) column; and
• You may enter the areas individually, or use the Apply-to options to fill multiple cells at once. This is explained in detail in the Using the Apply-to options section. You can also copy values from one cell and paste into other cells. Right-click on the source cell (the one you want to copy) and choose Copy. Then, right-click on the target cell, and choose Paste. The resulting table is shown in Figure 121.

When assigning FU areas manually using the Map tab, you can view the entire catchment and its outlines. FU areas can be assigned as follows:

• Click on a sub-catchment that you want to assign a model to, or highlight several using the mouse (drag and select). Alternatively, use Ctrl to select several sub-catchments. If you hover the mouse over a selected sub-catchment you will see the its number or name;
• To assign the area covered by each FU to the selected sub-catchments, select a cell in the table you want to assign the area to; and
• Use the Apply-to options to assign the same area to the selected sub-catchment/FU combinations.

If the areal percentages per sub-catchment, do not sum to 100%, the percentage cell turns pale red (to indicate an error) for that sub-catchment. In Figure 122, SC # 1 (Urban FU), the area percentage should be 50, not 5. The error applies only to SC#1, so the cell for SC#2 is not pale red.

Figure 123 shows the correct areal percentages for SC#1.

You can assign areas to multiple FUs simultaneously, using the Apply-to options on the right of the screen. This is useful when you have a large number of sub-catchments, each containing several FUs.

• In the Area (ha) or Area (%) column, click in any cell;
• Enter a value or percentage;
• Specify the appropriate values in the Apply selected cell to: options (to the right of the table); and
• Click Apply, and the value will propagate through the specified sub-catchments and/or FUs.

To assign FU areas using a raster:

• Click Load to upload a raster file;
• If the land use map does not include a mapping of grid code to land use, click Assign Mapping;
• In the resulting window, assign a FU to each grid code using the drop-down menu in the FU column (Figure 124); and
• Click OK to close the Match FU Definitions to Raster window.

For each sub-catchment, the FU areas MUST add to 100% (+/- 0.1%). If areas do not sum to 100%, cells in the Area column will be shaded pale red. An exclamation mark will also appear on the left side of the first column.

Rainfall runoff models (Steps 7-9)

The next 3 steps involve configuring the rainfall runoff models for every FU/sub-catchment combination. Refer to Assign rainfall runoff models for details on completing these steps. Click Next or Back to navigate between them. Note that on completion of step 7, the Finish tab at the bottom of the wizard becomes active, indicating that the information provided up to this point is the minimum data required to complete the wizard. Click Finish if you wish to complete the scenario.

Constituent models (Steps 10-11)

Here you configure the constituent generation models for each FU/sub-catchment//constituent combination. Configuring constituent generation models provides details on how to do this.

Filter models (Steps 12-13)

You now assign a filter model for each FU/sub-catchment//constituent combination. Filtering models represent for example, the effects of riparian filter strips, artificial wetlands, farm dams and similar management treatments. Fluxes from each FU can be passed through separate "filters". Refer to Configuring filter models for more details.

Assign link models (Step 14)

Just as FUs are assigned models in sub-catchments, you must also assign models to links (Figure 125). In this step, you assign each link a routing model. You can also assign an in-stream processing model for every defined constituent.

To assign a routing model to a link, click on the link and choose a routing model from the routing model drop-down menu. You can use the Apply-to options to apply the same link model to other links in the network. Figure 125 shows the available routing and in-stream processing models. To assign in-stream processing models to the links, click on the desired link, and choose the appropriate model from the drop-down menu in the Model column. Click Edit... to configure parameters for each of the routing models. For details on the available routing and storage models, see the Source Scientific Reference Guide. The items in the contextual menu have the same function as that described in the network definition step.

Click Apply To All to apply the configured settings to all links.

To check which model has been assigned to a link, click on the link. The link model will be displayed in the Routing model pull-down list. Click Next when the desired models have been assigned to all links.

Parameterise link models (Step 15)

To assign parameter sets to link models, select the link that was assigned a model in the previous step. Then, using the Parameters drop down list, follow the same process used for rainfall runoff and constituent generation models to generate parameter sets (Figure 126).

Designate a meaningful parameter set name to make it easier to select appropriate parameter sets when testing alternate scenarios.

Repeat the above for in-stream processing models.

Assign catchment models (Step 16)

This functionality is yet to be documented, if you would like assistance please call 1300-5-WATER (1300-592-837). Relevant to GWLag Plugin.

The default node type in Source is a confluence node, where the inputs to the node are the upstream sub-catchment outlets, and the output from the node is the current sub-catchment outlet.

Using the Apply-to options

This technique can be replicated for other Apply-to options available in the wizard. It can be used to:

• Assign a single value to all FUs across all sub-catchments;
• Assign a single value to all FUs in a particular sub-catchment (eg 50% of the total area is assigned to each FUs in sub-catchment #9);
• Assign a single value to all FUs of a certain type (across all sub-catchments); or
• Re-allocate FU areas by value or percentage. For example, if you have already specified that 50% of each sub-catchment is of FU type "Forest", and 50% is of type "Urban", you could model increases in urban encroachment by specifying Auto-increase by 5%, all FUs of type "Urban" at the expense of all FUs of type "Forest". See Figure 128.

Ensure that the percentage values for each sub-catchment sum to 100% prior to re-allocating FU areas.

Editing scenarios

Once a scenario has been created it can be edited using the Edit menu.

Note After a scenario has been created using the wizard, you cannot change the network itself, ie you cannot add or remove nodes or links, nor can you alter constituents.

The Edit menu gives you access to all the elements of a scenario that can be modified. Refer to the Constituent generation and filtering models and Rainfall runoff models chapters for further details.

Note If the FU list and areas are modified, the models, parameters and climate input data associated with them (ie rainfall runoff, constituent generation and filter models) will be modified as well. Check that any of these models, parameters and input data are assigned correctly.