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Pond is in wrong cell after deposition

When you’re modelling a TSF with multiple cells, its important that the pond is represented properly when modelling within a specific cell.  Consider the scenario below. The TSF is made up of two cells.  The perimeter dyke is at elevation 115m, and the splitter dyke is at elevation 114m.

Now we’ll deposit some tailings in the south cell. Deposition settings are shown below:

Once the deposition run completes we get some very strange results.  Instead of the pond being in the south cell where we’d expect it to be, its actually in the north cell.  When asked to select a pond, a location in the south cell was selected.  What is going on?

In this example, the problem is caused by the maximum containment elevation specified in the Pond tab of our deposition parameters.  The maximum containment elevation is used to work out the possible locations where ponds could end up. Once the point in pond is selected, the pond that contains this point is identified based on the elevation and the maximum  containment elevation.  Due to the maximum containment elevation being higher than the splitter dyke, it sees both cells as being available for water storage.  

These contours were created using the command Surface water/Info/Create contours inside basin, with a maximum pond elevation of elevation 115m.

If we want to keep the two cells separate, then when we’re specifying the maximum pond elevation in the deposition run, we need to make sure that the elevation is at or below the elevation of the splitter dyke.

After the deposition run completes, we get the following result, which is what we intended to happen.

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