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Figure 3-3: Options and parameters for assigning aquifer elevations in MAGNET. Default values/settings are shown.

3.3.1 Top Elevations

By default, the top elevation of the model follows the DEM of a resolution consistent with the model cell
size (e.g., if the cell size is ≥ 90m, the 90m resolution will be used, if the cell size is ≈30 m, the 30m
resolution will be used etc.). The user may also choose from 90m, 30m, 10m, and 1m (for select regions)
resolutions by accessing the drop-down menu next to ‘DEM Res.’

Choose the ‘Constant’ option and use the text box to enter the elevation to be used as the top boundary
throughout the model domain.

User raster files can also be used to represent the aquifer’s top surface. To do this, check the box next to
the ‘Import’ link, then select the link to open a file browser. Browse to and select the appropriate file for
importing. A prompt with file metadata will appear after the file has been uploaded, and the file path and
name will appear in the text box next to ‘Import’. If the units of the DEM are not meters, use the text-box
next to ‘multiplier to meter’ to enter the appropriate multiplier, e.g., to convert from ft. to m, enter 0.3048,
as 1 ft.=0.3048m.

3.3.2 Bottom Elevations

The bottom boundary of the model domain (aquifer bottom) can be assigned as:

• a constant value prescribed by the user (see Figure 3-4a);
• a surface following the aquifer top elevation surface such that the aquifer has a constant thickness
(Figure 3-4b);

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