NDR: Nutrient Delivery Model

DanielDaniel Member
edited October 2016 in Terrestrial Models
Hi to everyone,
I am running successfully the NDR Model. The nutrient run off proxy (precipitation in mm) has been has been used for the year 1998.
Now I am trying to implement a more precise precipitation data based on regional monitoring stations (point features). I used Kriging technique in ArcGIS to generate a new raster layer.
The NDR runs smoothly. When I open the output "watershed_results_ndr" the shp gives for the n_load_tot = 16322354.762069 and for the n_exp_tot = 0.
This cannot be correct.
Can you help me out?

for the support,

3070 x 2302 - 217K
3070 x 2302 - 266K
Post edited by Daniel on


  • RichRich Administrator, NatCap Staff
    edited October 2016
    Hi Daniel, that export value seems odd; I would guess maybe a DEM routing issue?   (not sure if the magnitude of the load is off though, I don't have an intution about that). 

    Can you dropbox me your data stack so I can run it on my end to see if I can recreate the issue?
    Post edited by Rich on
  • PerrinePerrine Moderator, NatCap Staff
    Hi Daniel and Rich, 
    Also good to check the the value of the "modified load" or the "runoff proxy index" rasters, in case the issue comes from this module (loads are multiplied by the runoff proxy index factor to account for heterogeneity in runoff production throughout the landscape).

  • DanielDaniel Member
    edited October 2016
    Hi, thanks both for your answer. Can you send some contact, I will send you the dataset.
    Post edited by Daniel on
  • RichRich Administrator, NatCap Staff
    Oh sorry!  Please dropbox me here: richsharp@stanford.edu
  • RichRich Administrator, NatCap Staff
    Hi Dan, I wasn't able to duplicate your 0.0 export value, but it may be because I was using a different flow accumulation threshold value than you might have (I used 1000 as a default).  However, I do see that the flow direction and flow accumulation rasters are fairly noisy which is a the DEM that has hydrological pits and doesn't numerically drain.  (see http://i.imgur.com/bRne470.png for the results I got on your DEM)

    Can you take a look at your flow direction/flow accumulation rasters in the intermediate_output folders?  That may help debug the issue on your end.  The solution could be to fill the DEM using SAGA or ArcHydro.  

    I hope that's enough info for you to proceed, it otherwise doesn't look like a software bug on our end.  Let us know if we can help further!

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