Problem

Is it possible to select all catchments upstream of a certain element?

When using the "trace upstream" query, upstream catchments are not selected. Is it possible to select them?

Solution

Currently, catchments that are assigned to nodes via the "outflow node" property are still not considered as being "upstream" and will not be selected when using the "Trace upstream" Network Navigator query. One possible workaround involves the use of the ArcGIS platform, available with SewerGEMS:

1) Open the model in SewerGEMS for ArcMap
2) Start an Edit session on the SewerGEMS model geodatabase
3) Go to SewerGEMS > View > Network Navigator.
4) Under Network Trace, choose "Trace Upstream", then select the desired downstream element (the element whose upstream catchments you want to select)
5) Click the "select in drawing" button
6) Go to the Selection menu and choose "Select By Location".
7) Choose to "select features from" the catchment layer, that are "within a distance of" the catch basin layer. If the catchments are closer to the conduits or if you're using manholes, select that instead. Be sure to check the box for "use selected features", so that it considers the elements that the query just selected. Enter an appropriate tolerance, which will be the distance between the catchbasin and the catchment. You'll need to choose a distance that's large enough to select catchments that should be selected, yet small enough so as not to select catchments that should not be selected (that aren't actually upstream of the elements selected by the query).
8) Click Apply > OK - the upstream catchments should now be selected.
9) At this point, you can right click in the drawing (using the SewerGEMS Select tool), choose "edit group" and open the catchment table. it will be filtered to show only those catchments. Or, if you'd like to create a selection set for future use, right click in the drawing and choose "Create selection set".

Alternative Approach using Excel

An alternative option would be to export the catchment and catchbasin data to Excel (all catchment labels and their outflow node labels, and catchbasin labels within your desired run of pipes), use Vlookup in Excel to flag the catchments with a matching catchbasin, then import that back into the catchments via ModelBuilder as a User Data Extension (UDX) and run a query to select catchments with the flagged UDX attribute.

See Also

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