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Interpreting Output from Nutrient Retention Model

JonJon Member
edited August 2013 in Terrestrial Models

I've been running the new standalone nutrient retention model (I just upgraded to 2.5.5 64 bit today), and I wanted to get confirmation on the meaning of the output. The documentation refers me to a table (Output\nutrient_watershed.dbf) and fields (nut_export (kg/watershed, not /ha) AND nut_retain (kg/watershed, not /ha)). The model instead produces watershed_outputs_SUFFIX.shp, which includes fields called n_adjl_tot and p_adjl_tot, but doesn't seem to have a split between retained and exported.

Is this new field the sum of nutrients exported and retained, and if so where /how can I get a watershed level summary of nutrient export? I'm guessing that n_adjl_tot is not nutrient export, since the values are much higher than they should be for export and my water yield calibration went pretty well. Let me know, thanks,

Jon Fisher


  • PerrinePerrine Moderator, NatCap Staff
    Hi Jon,
    There are some inconsistencies in the names of the outputs, we are currently fixing this. In the meanwhile, you should still find the information you need in the output tables.
    *n_exp_tot is the total N export (per subwatershed)
    *n_adjl_tot is the adjusted N load (per subwatershed): as described in the user guide, the load inputs are actually adjusted by a hydrologic sensitivity score (HSS)
    *n_ret_tot is the total N retention in the subwatershed.
    Summing up export and retention should give you the adjusted load.
    I hope this helps,
  • JonJon Member
    n_exp_tot and n_ret_tot have values of -1 in my output table, and the output tifs have a mix of holes (no data), really high values, and really low (negative) values.
  • PerrinePerrine Moderator, NatCap Staff
    Hi Jon,
    Apologies for this. The software team has recently found a bug in the standalone version: the routing does not work properly and it could explain why you get these weird values.
    They are working to fix this as soon as possible! In the meanwhile, we can advise to use the ArcGIS model if you have access to it.
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