Climate only TFN model tutorial

Overview

This tutorial presents the steps for build a time-series model of a groundwater hydrograph using a transfer function noise model time-series models where the groundwater level elevation is only influenced by rainfall and evaporation. The tutorial uses data from an example model built into the HydroSight GUI, specifically Bourke Flat. Follow this tutorial to build your own model using this data, or alternatively use the HydroSight GUI example titled TFN Model - Landuse change to inspect the complete model.

The major steps are:

1. preparing the input data;
2. building the TFN model;
3. calibrating the built model;
4. using the calibration results to assess the reliability of the model;
5. using the model to perform simulations.

In the following each of these steps is detailed.

The input Data

The TFN models require the following three input .csv files. See Data Requirements for general format requirements. The tasks for this step are:

1. Download the zipped example data from here.
2. Create a project folder on your computer.
3. Unzip the example data into your project folder.
4. Open each of the three .csv files within a spreadsheet and observe the following aspects of the HydroSight data requirements:
   • The head file (obsHead.csv) data column BoreID allows multiple bores to be within a single file. This file has two bores listed.
   • The head data can be of an irregular monitoring frequency.
   • The water level observations must be an elevation, not depth.
   • The water level observations start in 1983.
   • The forcing data file (forcing.csv) left three columns are Year, Month and Day. The columns are essential and must be in this order and named as such.
   • The forcing data file right three columns are Rain_mm, FAO56_PET_mm and Landuse_change_frac. Theses columns can have any name and are the forcing data available for input to the time-series model.
   • The forcing data file has the following requirements: a daily time step, no time-step gaps and the first data point many years before the first water level observation, which in this tutorial is 1983.
   • The coordinates data file (coordinates.csv) must have the following three columns: SiteID, Easting and Northing. The rows must list the location of all observation bores within the head .csv file and all columns within the forcing data .csv file and the SiteID inputs must be identical to that within the respective files.
   • The coordinates file easting and northing is, currently, only used when modelling pumping drawdown. For climate only models the coordinates can be any number.

Building the Model

To start building a time-series model of a groundwater hydrograph complete the tasks below:

1. Open HydroSight.
2. Click on the tab Model Construction.
3. Set the project folder to where the input data was saved using the menu File > Set Project Folder.
4. In the column Model Label, enter a title for the model. This can be anything but must start with a letter and be unique to the other model labels within the project. In this example let's input "controlCatchment_model1".
5. Input the head file by placing the cursor in the next cell to the right (column Obs. Head File). This should open a file selection window showing the files within the project folder. Use it to select the file "obsHead.csv".
6. Input the forcing file by placing the cursor in the column Forcing Data File. This should also open a file selection window showing the files within the project folder. Use it to select the file "forcing.csv".
7. Input the coordinates file by placing the cursor in column Forcing Data File. This should also open a file selection window showing the files within the project folder. Use it to select the file "coordinates.csv".
8. Select the bore to model by placing the cursor within the column Bore ID. This should cause a white box to be displayed on the right that lists all bore IDs within "obsHead.csv". Click on "Bore_6416" to select it for this model.
9. Select the type of time-series model using the drop-down in the column Model Type. Notes, when you select a model type, a text box should be shown on the right giving a summary of the selected model type. For this tutorial select the option "Model_TFN".

Now that the inputs and type of model are defined, the form of the TFN model can be defined by placing the cursor within the column Model Options. This will display input box(es) on the right that are specific to the type of model (see screen shoot below). For TFN models the primary inputs are to transform the input forcing data (e.g. transform precipitation into free-drainage), weight input or transformed forcing data to fit the observed hydrograph. Below are the tasks for defining the model options:

1. Within the top-left box (see red "1" above), use the drop-down to select the type of transform to use. In this tutorial use "climateTransform_soilMoistureModels" (see here for model details). This will add a single storage soil moisture model to the time-series model.
2. Place the cursor within the column "Input Data". This will display a grid below it. The left column of the grid lists the possible inputs for the model, which are precipitation, potential evapotranspiration and the fraction of the landscape influenced by the land cover being investigated. In this tutorial only precipitation, potential evapotranspiration are required. Hence, use the drop-down option in the right column to input Rain_mm to the first row and FAO56_PET_mm into the second row. For the input TreeFraction input "(none)" to turn this feature off within the model.
3. Place the cursor within the column Options to display options for setting the soil model parameters (see red "2" above).

Calibrating the Model

Assessing the Model Calibration

Model Simulations