Automatic Correction of Negative Depths

Flow passing over very steep slopes may cause the depth of computation cells to become negative. Once a few cells have negative depths, the problem usually gets progressively worse, leading to a large positive (too much water in the model) mass error. The correct_negative_depths option aims to correct negative depths greater than -1mm by taking water from adjacent wet cells.

At each 2D time step, the depth of all active cells is calculated. If a cell's depth is negative (greater than -1mm), volume is taken equally from adjacent wet cells in order to bring the cell's depth back to zero while conserving volume within the model.

The following code snippet shows the correct_negative_depths option towards the end of an XML file:

...
</output_results>

</domain>

<advanced_options>

<correct_negative_depths/>

</advanced_options>

</ISIS2Dproject>

The correct_negative_depths tag is only available when using the ADI solver.