I’m using the NDR model to assess nutrient export in relation to changes in precipitation.
I’m using a raster showing the average annual precipitation over my study area. This is my Nutrient runoff proxy. In QGIS, I created a new raster file that shows an increase of rainfall of 25%.
In other words, I ran the NDR model twice: using the “average annual precipitation” as proxy and the “average annual precipitation +25%” as another proxy.
The problem is that the results of nutrient exports are almost identical between the two runs. It seems to me that an increase in precipitation does not change nutrient export, probably because this proxy represents “the spatial variability in runoff potential”, but I wonder if I’m correct.
I utilized different DEMs with different resolutions, the coordinate systems are correct, and I also changed the Threshold flow accumulation values.
Thank you for your help.