Watershed delineation from a DEM

Question

Hi

I have spent the last hour or so trying to find the answer. I have a DEM derived from LiDAR that my client wants to have updated watersheds produced from.  I have run the Fill, Flow Direction, Flow Accumulation, but the next step is to run the Snap Pour Point tool, I do not have points, and my area is large, no way to manually add points, how do I continue..

I found the "Watershed" tool in Pro, do I just use that as my next step? if so it asks for the pour point data (raster) if no points, but I am not sure what raster to use.. is it the flow accumulation one? or....

I am lost.. sorry I am not familiar with creating watersheds and need some guidance.

Thanks in advance.

Tina Kwitkoski

imanebenromdhane · Answer

I am waiting for news from you and I wish you success and that you progress
in your work

TinaKwitkoski · Answer

I will definitely try this.. thank you for the workflow.. I will let you know if it works.

imanebenromdhane · Answer

Hi, Tina

Thank you for reaching out, and I appreciate your efforts in trying to find a solution. I understand that you are working with a LiDAR-derived DEM and are in the process of creating updated watersheds for your client. I'm here to help guide you through the next steps.

Since you've already performed the Fill, Flow Direction, and Flow Accumulation processes, the next step involves identifying pour points for the Snap Pour Point tool. However, considering the large area and the absence of manually added points, you can indeed utilize the "Watershed" tool in ArcGIS Pro for this analysis.

When using the Watershed tool, it typically requires pour point data. If you don't have specific points, you can use the output from the Flow Accumulation tool. The Flow Accumulation raster represents the accumulated flow to each cell and can serve as a reasonable substitute for pour points in the absence of specific points.

Here are the steps you can follow:

* Open the "Watershed" tool in ArcGIS Pro.
* For the "Input Flow Direction Raster," use the output from the Flow Direction tool.
* For the "Input Flow Accumulation Raster," use the output from the Flow Accumulation tool.
* Specify an output location and run the tool.

This approach allows you to derive watersheds based on the flow accumulation values without manually adding pour points.

Feel free to adjust the parameters based on your specific requirements, and let me know if you encounter any issues or have further questions. I'm here to assist you through the process.