catchment area delineation

Hello eslam NOH,

Catchment Delineation needs to know the slope of the surface to be able to know where the water flows, so it needs elevation information to do that.  If you don't have a Digital Terrain Model (DTM) to use with Catchment Delineation, Catchments can be placed in your model from the Place Catchment command (Layout - Catchment).

Simply place your Catchments in your model and link them to Catch Basins (as outflow elements).  More information on how to accomplish this can be found in this Wiki article - Entering catchment data directly to a catch basin.

I have added this information to the Using Catchment Delineation wiki article for future reference.

If this does not answer your question, then please elaborate on the source of elevation information you have and we will help guide you as to the best way to accomplish what you are trying to do.

Thank-you,
Larry

To add to Larry's reply - if you do have some kind of elevation information, please describe what you have. As an example, see this recent post from another user, who had X/Y/Z information about the ground surface in a spreadsheet. That could potentially be converted to a form that the Terrain Model feature can use, for catchment delineation. For example you could use an external application to convert to a DTM/DEM/TIN/Shapefile.