Bsum raster with negative values. Help to understand it?

Hi there again,

trying to understand the results from SWY model... if when the local recharge is
negative, then the pixel did not contribute to baseflow so B is set to
zero, how can be explain to get negative values in the Bsum raster? Any thoughts , please?

Thanks a lot


  • RichRich Administrator, NatCap Staff
    Hi Raquel, I think this might be a bug in the model that I have in my queue to fix.  @perrine, is this The Bug?
  • RichRich Administrator, NatCap Staff
    p.s. I'll post here when I get to a patch. It's a bigger issue than most so will take some time.
  • Hi Rich!
    Thanks a lot!!  I'll keep on eye on the post ;)
  • PerrinePerrine Moderator, NatCap Staff
    Hey there, 
    This may be a related issue indeed.
    Raquel, we are working on an issue with the model, which sets L_avail values to 0 when they should be allowed to be <0. Looking at the model equations, this issue will likely affect Bsum too. 
    Sorry for the inconvenience and we hope to post some good news soon!
  • Hi Perrine,

    Thanks for everything. Just a question in the meanwhile. My Bsum raster is somehow useful or it is better if I don't use it?
  • PerrinePerrine Moderator, NatCap Staff
    I think it's best not to use it since we don't know exactly how it will change with the model fix.
    Thanks for your understanding,
  • Thanks again Perrine.
  • Perrine and Rich, appart from the  SWY documentation and the poster "The value of simple models: development of a seasonal water yield model to inform ecosystem-based management", is there any other document or article I could read about the implementation of the model?
  • swolnyswolny Member, NatCap Staff
    Hi Raquel -

    For a national ES assessment in Myanmar, we used the SWY model, and a technical writeup can be found in our publication library, here

    ~ Stacie
  • Thanks Stacie!
  • Hey Rich and Perrine, just checking - what is the status of The Bug in SWY?
  • PerrinePerrine Moderator, NatCap Staff
    "Never been closer" :)
    Rich has fixed the bug and if I'm not mistaken there's only one minor change to make before we can re-release it. Will post an update on the forum.
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