I am working through the NDR model and am just confused about the Subsurface Maximum Retention Efficiency. Are there any recommended values? I would guess that the higher the efficiency the less subsurface export, so if I want my model to reflect only surface runoff would I set this value to 1?
Second questions: Can anyone explain this to me better?
" Note 2: Load values may be expressed either as the amount of nutrient applied (e.g. fertil-
izer, livestock waste, atmospheric deposition); or as “extensive” measures of contaminants,
which are empirical values representing the contribution of a parcel to the nutrient budget
(e.g. nutrient export running off urban areas, crops, etc.) In the latter case, the load should
be corrected for the nutrient retention from downstream pixels of the same LULC. For ex-
ample, if the measured (or empirically derived) export value for forest is 3 kg.ha-1.yr-1 and
the retention efficiency is 0.8, users should enter 15(kg.ha-1.yr-1) in the n_load column of
the biophysical table; the model will calculate the nutrient running off the forest pixel as
15*(1-0.8) = 3 kg.ha-1.yr-1."
I am obtaining my export coefficients from empirical values so I should be scaling them like this?