Nutrient Retention Outputs for Standalone vs Arc

admin

Hi all,
I have tried to run the Nutrient Retention model with the last Standalone release 2.6 with my own data.
It's working fine but did not create the retention and export for sub-watershed.
The sample data give me the same, just the summary on the main watershed, not the sub-catchments results.
I also tried the last standalone version 2.5.3 with any success.
What should I do if I want the same result (retention and export by sub-watershed) that give me the ArcGis version?
Could zonal statistic be useful and appropriate to do that?

Cheers,
Andrea

@IceAge

swolny

Hi Andrea -

Yes, you can use Zonal Statistics on the results Intermediate\p_retention.tif (or n_retention.tif) and Output\p_export.tif (or n_export.tif), using your sub-watersheds to agggregate. You will get the same results as the ArcGIS version.

~ Stacie

Doug

We currently have taken out sub-watersheds from the Nutrient and Sediment stand alone model because those values get derived from the watershed. Another option is to run the model again, this time with the sub-watershed shapefile as your watershed input. Don't forget to set the shapefile field to have the proper attribute 'ws_id'!

IceAge

Ok Doug, but what will become my watershed in this usage scenario? A same layer as before with only the attribute ws_id?

IceAge

Doug, imagine I run a huge zone setting as watershed my sub-watershed (with ws_id attribute modified for this purpose), the new version of Invest (3.0) still have the limitation of maximum sub-watershed size 4000x4000 cells with cell size equal to the smallest cell size of your input layers?

Doug

Currently, in order to get results for a subwatershed region, you would want to use your subwatershed shapefile as the watershed input to the models. Since the model looks for a field 'ws_id' in that shapefile, you would want to edit the subwatershed shapefile to have the field 'ws_id' as well.

The new stand alone models do not have any geoprocessing limitations, and the subwatershed shapefile can be of any size but should be consistent with what is found in the watershed region or, from a tool used to delineate the subwatersheds. If there is a size / geoprocessing issue within the model we want to know so we can fix it!

Cheers