terrain model and catchment delineation

Hello Dima, 

The error message implies that the units in the terrain model settings are not matching that with the model units. Could you please confirm? 

Also make sure that you are following the correct procedure to perform catchment delineation, per steps mentioned in below wiki. 

Using Catchment Delineation 

If required please upload model files and terrain model file for our testing. 

Sharing model files.

Thank you for your answer.

I have checked the units and didnt see any mistake. I am sending the file now through the confidential files

thank you

Thank you. It did help me resolving the problem I mentioned above.

I get really small areas for most of the catch basins, the catchment does not cover the entire area of the drawing.

When you ran the program for me was it the same for you? Do I have a problem at the properties of the catchment delineation or is it the topography?

Thank you

Hello Dima, 

Please run trace downstream tool which will trace and display the surface water flow direction across the terrain, to make sure inlet allocation is correct. 

Incorrect placement of inlets will cover less area, try moving around inlets and rerunning to tool to see if it makes any difference. 

Placement of inlets plays an important role in catchment delineation, which is explained in detail along with examples in below wiki. Please make sure you are following the procedure correctly. 

Using Catchment Delineation

I understand and yes if I move them the catchment changes, but those catch basins I have, they are already in their real location, it doesn't make sense I try to move them to the location of the downstream because I might not get accurate results of how much flow flows through each catch basin

I too am having the same problem in SewerGEMS when trying to develop storm sewer catchments. I have an existing model, with CBs in their correct actual location and can't just move them around. 

This tool appears to be useless to develop a complete storm sewer catchment area for an existing system. It just produces a whole bunch of skinny finger catchments, and doesn't cover the area properly.

Bentley folks, any suggestions?

Hi Andrew,

See the section in this article titled "Delineating catchments for existing catch basins". You can select your existing catchbasins, right-click and select "Update Catchments for Inlets".

If you are getting small skinny catchments, that may be an indication that your catchbasins are not located at sag points. With the delineation tool, the resulting catchment shows the area of the terrain that would drain to that specific point. So, when a catchbasin is placed in the middle of a sloped area, in most cases only a skinny "channel" uphill of it will drain to it, leading to the symptom you describe. Using the downstream trace tool can help you better understand how the water flows

Hi Andrew,

See the section in this article titled "Delineating catchments for existing catch basins". You can select your existing catchbasins, right-click and select "Update Catchments for Inlets".

If you are getting small skinny catchments, that may be an indication that your catchbasins are not located at sag points. With the delineation tool, the resulting catchment shows the area of the terrain that would drain to that specific point. So, when a catchbasin is placed in the middle of a sloped area, in most cases only a skinny "channel" uphill of it will drain to it, leading to the symptom you describe. Using the downstream trace tool can help you better understand how the water flows