To calibrate an existing MODFLOW model including transient data, use the following steps:
| 1. Enter transient data into the Map module.
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| 2. Import transient data.
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- Select the Map module coverage that will receive the transient data.
- Use File | Open... to open files with transient data.
- Use the Text Import Wizard to specify how to import the data.
- In step 2, select a transient GMS data type.
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| 2. Initialize MODFLOW stress periods.
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| 4. Create observation data.
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| 1. Create an observation coverage.
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- Create a coverage with at least one Observation Points option turned on.
| 1. Create new coverage from scratch.
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- Use the New Coverage right-click command.
- Use the Coverage Setup dialog to create a new coverage by selecting the desired coverage properties and naming the coverage.
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| 2. Create new coverage from an existing coverage.
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- Use the Duplicate command on an existing coverage. This will copy any feature objects on the coverage.
- Use the Rename command to give the coverage a new name.
- Change the coverage setup.
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| 2. Create observation points or arcs.
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| 1. Create feature points, arcs, nodes and vertices.
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- In the map module, create feature objects in the active coverage.
- Use the Create Arc
 tool to create arcs in the map coverage.
- Begin creating a new arc by clicking in the graphics window at either arc end. If clicking on an existing feature node, vertex or arc, the new arc will snap to that object.
- Double-click or press the Enter key to terminate the arc.
- Use the Create Point
 tool to create additional nodes alone or to split arcs.
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| 2. Modify arcs.
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- Feature arcs, whether digitized or incorporated from a boundary condition or a material coverage, often need to be edited after initial creation.
| 1. Create additional vertices on arcs.
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- Use the Create Vertex
 tool to add vertices along arcs.
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| 3. Split arcs.
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- An existing arc can be split by:
| 2. Add a node to the arc.
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- Use the Create Point tool to add a node on an arc in order to split it into two arcs.
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| 3. Connect the end of an existing arc to the middle of the arc.
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- Use the Select Points\Nodes
 tool to drag the node of an existing arc to anywhere in the middle of another arc. This will split the second arc into two arcs.
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| 4. Add a new connecting arc.
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- Use the Create Arc tool to start or end a new arc on an existing arc to split the existing arc into two arcs.
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| 3. Set observation point or arc attributes.
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- With the Select Point/Node tool, right-click on the observation point and select the Attribute Table command.
- Set the observation attributes in the Attributes Table dialog.
- With the Select Arc
 tool, right-click on the observation arc and select the Attribute Table command.
- Set the observation attributes in the Attributes Table dialog.
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| 5. View observation data.
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- Create a plot of the observed data and note calibration values by doing the following:
| 2. Select available plot type.
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| 1. Computed vs. Observed Data plots.
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| 2. Residual vs. Observed Data plots.
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| 6. Change parameters.
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| 1. Change model parameters.
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- Model parameters are usually adjusted in the Map model on the appropriate coverage—usually the coverage with recharge or hydraulic conductivity values.
- With the Select Arc , Select Point/Node , or Select Polygon
 tool, right-click on the desired feature object and select the Attribute Table command.
- Adjust the attributes in the Attributes Table dialog to calibrate the model.
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