Scales

Viewing TWODAN Models at Various Scales

A key advantage of TWODAN over finite-difference and finite-element modeling methods is the capability of quickly and conveniently modeling groundwater flow at multiple scales using a single model. The following example shows model simulation results at regional, local and detailed scales.

Regional Scale

The model presented in this example includes various elements representing constant-head boundaries, heterogeneity and a resistant barrier (elements shown in green). The graphic below shows simulation results at a regional scale.

Regional Scale
Simulation Results at Regional Scale

Head-specified linesinks form constant head boundaries at streams, ponds, and wetlands.

A high conductivity glacial outwash valley aquifer is represented by a heterogeneity in the upper right area.

A well with a U-shaped resistant (leaky) barrier is within this heterogeneity.

Local Scale

The following graphic presents the same model and solution as above at a local scale (i.e., just a different, smaller window chosen for the plot).

Local Scale
Simulation Results at Local Scale

The heterogeneity is shown in green.

The barrier is shown in blue.

Streamlines (groundwater flow paths) are shown in red.

A basemap is shown in yellow.

Detailed Scale

The plot shown below presents the same model, but focuses on the extraction well and resistant barrier at a detailed scale.

Detailed Scale
Simulation Results at Detailed Scale

Note the accuracy of the solution near the well and barrier despite the large extent of the entire model. This level of accuracy and flexibility with model boundaries is not found in finite-difference or finite-element numerical methods!

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