Please, I have been worried about my results. I ran the InVEST Water Yield model for 10 years interval, that is 2002, 2012 and 2022. The per-pixel output is what is concerning me, and I am not sure whether the results are correct or not. For 2002 and 2012, the per-pixel values range from 0 upward, but for 2022, it range from 60 upward. Could this be correct maybe as a result of different precipitation and evapotranspiration that occurred a over decade (1993-2002, 2003-2012 and 2013-2022)? I think the water-yield results for all years were supposed to start from 0. or could this be normal. i have attached for better understanding.
It is completely normal for the lowest value of water yield to be something other than zero. As you say, it depends a lot on the difference between precipitation and evapotranspiration. So if you want to understand those values, look at your model inputs in GIS, compare them with the result values, and see if the difference in values between decades makes sense to you.
To understand in more detail, consult the User Guide model description section to see the equations that are used, and the model outputs additional rasters (like aet.tif) that correspond with the different steps leading up to the water yield calculation.
