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Interpret NDR model results

Hi, I am an NDR model user. After the model runs, I post a message to discuss the results.

From the model results, we calculated the purifying efficiency of N and P of city area 

It's about 76%.

I can not understand why the results efficiency is so high., so I want to get some advice from the natcap team.

If there is a similar study result or if you know why, please explain.

Thank you!


  • swolnyswolny Member, NatCap Staff
    Hi @ysunparc -

    The resulting efficiency is very dependent on the values that you provide for "eff_n" and "eff_p" in the biophysical table. High values for those mean that each pixel of urban area is very efficient at removing N/P that enters that pixel from upslope, and you will see high values in the model results. What values did you provide for eff_n and eff_p for city areas?

    ~ Stacie

  • Hi Stacy,

    I was also wondering about model result interpretations. For some of my watersheds where I have mainly forest (low N load, high N efficiency) I am getting negative retention values (i.e. export is greater than loading). I can't understand what might be driving these results. Any ideas?

  • swolnyswolny Member, NatCap Staff
    Hi Sylvia -

    Are you comparing n_exp_tot and n_load_tot in the watershed_results shapefile, or calculating some other way? It doesn't make any sense that export would be greater than loading anywhere, much less in that kind of forested landscape. 

    ~ Stacie
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