Flow Accumulation with Adjusted Flow Direction in Streams Grid not working

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04-21-2014 11:18 PM
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MariaKottermair1
New Contributor
Hi, I ran the "Adjust Flow Direction in Streams" tool which worked fine. When I try running the flow accumulation with the adjusted flow direction grid as input, it only works when I run it for a small area but not for the entire area of interest. But if I run the flow accumulation with the regular flow direction grid (not the adjusted one) as input, it works fine (even for the large area). I'm using ArcGIS 10.1. Any idea why that is? Thanks for your help, Maria.
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BarbaraRuppel
New Contributor

I am having the same issue.  Have you had any assistance on this?  I'm really having a hard time finding any help or documentation on the new tools that have been included in ArcHydro.  I am like you and have been able to finally get all the tools to function correctly except the flow accumulation grid using the flow direction grid created by the 'Adjust Flow Direction in Streams".  Any assistance with this would be really appreciated.

Barb

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ChristineDartiguenave
Esri Contributor

The Adjust Flow Direction in Streams tool replaces the flow direction values in the cell located in the streams with the values from the input strfdr (stream flow direction) raster. This raster is created by the tool Create Drainage Line Structures based on the input stream features provided as input. It ensures that once the water reaches a stream cell, it flows along the digitized direction of the streams.

The process to ensure that the stream flow direction raster matches the flow direction grid it is mosaicked into is as follows (no sinks or lakes):

- Create Drainage Line Structures (Make sure the streams can exit the dem or they will be filled in)

- DEM Reconditioning from Stream Grid (using strlnk output from previous tool) - geoprocessing tool only. This tool is not in the toolbar.

- Fill Sinks

- Flow Direction

- Adjust Flow Direction in Streams (using strfdr)

Christine Dartiguenave

Esri Water Resources Team

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BarbaraRuppel
New Contributor

Christine, thank you so much for your help! 

I am going to try the process you described.  I do need to add one additional process and hope you can tell me where I should place it. 

I need to build walls using the 12 digit watershed boundary feature class.  Would I do this after the DEM reconditioning from Stream Grid and before the Fill Sinks? 

Thanks,

Barb

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ChristineDartiguenave
Esri Contributor

This is correct. You need to do it after the reconditioning and before the Fill Sinks.

Make sure you breach the walls with your streams.

Christine

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