# Study creation

A study is created from a model and describes one or several injections on the ground surface, inside the unsaturated zone or directly into the groundwater. Transient infiltration can also be modeled.

## Computational database

A new study is created by using the Thyrsis menu, selecting the New menu and the name of the model previously created (Figure 24).

Figure 24 New study creation

A project name must be chosen and a study directory where the computational database and all the results will be saved.

THYRSIS creates a new QGIS project and load it (Figure 25).

Figure 25 QGIS canvas at the creation of a new study

The model is displayed and a new tab is opened on the left.

## Simulation parameters

The study uses the default parameters associated to the hydrogeolgical models (cf Model parameters) but these parameters can be modified either directly by modifying the parametres table, or by editing the Latin Hypercube menu (Thyrsis>Create>Latin Hypercube) which can also be used to generate several sets of parameters in the context of uncertainty study. For each parameter a reference value, a minimal and a maximal value and a variation law should be defined.

For the tutorial simulations, we suggest the parameters of Figure 26.

Figure 26 Parameters definition for a new study

## Injection

Injection characteristics are defined through the THYRSIS panel described in the user manual.

For this tutorial we will define a HTO flux on an unique injection zone.

The HTO is selected via the chemical element combobox.

The injection is defined by clicking on the Flux button (Figure 27).

Figure 27 Injection buttons

and filling the form with the following values :

- Begin : 01/01/2012

- Duration : 0.00021 year (can also be defined in month, or day)

- Flux : \(9.8 10^{-9}\) (enter `9.8e-9`)

- Area : 59 (or use the pen that allow to draw the area on the map)

- Location : use the \({\odot}\) button and click on map to define center of the injection

- Depth : 0

- Water volume : 0

Then click on the Save button : the injection zone is added to the injection layer.

## Simulation and results

To launch simulation, click on the engine button . After the calculation, a resultats layer is added to the canvas.

The ZNS tab is opened showing simulated concentrations displayed on an 1D column (Figure 28).

Figure 28 ZNS tab

The time control bar (Figure 29) and the result control bar (Figure 30) of the THYRSIS menu bar are updated :

- the time combobox is filled with the simulation dates,

- the result combobox and the unit combobox are updated with the informations of the simulated variables.

Figure 29 Time control bar

Figure 30 Result control bar

The results can be displayed in the canvas (Figure 31) and in the 1D window (Figure 32) at any simulation date through the time combobox or by using the arrows in the menu bar.

Figure 31 QGIS canvas with simulation result

Figure 32 1D graphic

at any simulation date through the time combobox or by using the arrows in the menu bar.

Futhermore a 3D canvas can be used to display results (Figure 33).

Figure 33 3D graphic

Note

3D scene can be configured through the 3D parameters tab. To display OpenStreetMap background map on 3D scene, add OpenStreetMap to the QGIS canvas and activate Texture check box.