Water yield model results make no sense

I was running the hydropower water yield model with InVEST 3.7 on Mac.
I got results, but to me they don’t make sense. Especially when considering wyield_vol, which only amounts 0.020 m3.
Also wyield_mn is very different from the output\per_pixel\wyield_.tif.

I did various runs and tried to improve my input files to catch the error but no change in output.

InVEST-Hydropower-Water-Yield-log-2019-12-05–10_10_28.txt (17.4 KB)

Hi @fipsi2000 -

Is wyield_vol from the aggregated watershed results? Is the value of 0.02 m3 for the whole watershed, or a sub-watershed? Are your inputs in a projected coordinate system (with linear units of meters) or geographic coordinate system (units of degrees)? They should be in a projected coordinate system, or the calculations for volume will be weird (and probably very small) when trying to calculate volume over degrees instead of meters.

wyield_mn is the mean per-pixel value within the watershed/sub-watershed. When you say that it’s very different from wyield.tif, did you use Zonal Statistics to calculate the mean wyield.tif value within the watershed/sub-watersheds and found it to be different than what the model output?

~ Stacie

Hi Stacie,

the value of 0.02 m3 was for the whole watershed. But indeed the error occurred because I used a geographic coordinate system with units of degrees.

And regarding the wyield_mn output, I misinterpret the data.

Thank you!