what is the minimum value of threshold for DEM based stream definition?

[kazi rahman]

Hello All

For a biodiversity research we need to get information( landuse-soil-slope ) for each 500 m segments of the river of my study area. Therefore as a first step ( in the watershed delineation) part I use 100 as threshold and with the reach file obtained we made segments of each 500 m and one outlet for each 500 m segment.

Later when we use the outlet table generated (around 8000, please see the table) for each 500 segments it ends up with an error message . My specific question is what is the minimum threshold value that we can use for DEM based stream definition?

I am almost  sure that I didn’t make any mistake calculating from xpr ypr to lat long. And I also followed the same table structure from the default table structure. We are almost stuck this stage to see this error message included

Let me know if anyone of you have faced this kind of error message

With many thanks

Kazi

[Zé]

Hello Kazi,

If i am not mistake, tha ArcSWAT gives the minimum and the maxim valor
for the threshold value.
It is shown just below the window to wirte the value (that is given
already the default).

Zé

>  Doc1.docx
> 1030KViewDownload
>
>  outlet.dbf
> 900KViewDownload

[kazi rahman]

I do not think its the minimum and maximum value!
because i have tested with much lower values given in minimum and it works fine!

as an example for a watershed of 5367 sq km the mimimum default value comes 10248( of course it depends on DEM) and the lowest value comes 2480 but I used 100 in order to replicate all the tributaries existing in the river geometry file
it works fine if i select the outlet from SWAT delineated points but the problem start if I use user defined outlet.. thats why i wanted to know what are the consideration I should select on choosing threshold values!

I found threshold value selection is most sensitive if we work with user defined outlet, for another project we made several trial in order to find a suitable threshold value..

however, thanks for your kind response..

Kazi

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