RIOS preprocessing

jgoldsteinjgoldstein Member
edited January 2015 in RIOS
We are using RIOS in Iowa to look at targeting watershed activities at two scales - a larger one covering 4 HUC-10s for which we've completed the preprocessing toolbox, and a smaller scale covering roughly half the area for which we have not yet done the preprocessing.

We know that it's easy to put in the watershed area boundary in the toolbox and produce new preprocessing outputs just for the smaller area.

However, we are wondering if you can just take the preprocessing outputs for the larger region and clip them to the boundary of the smaller region and use these as inputs for the RIOS runs - in other words, not doing a new preprocessing run to produce outputs for just the smaller region.

We ask mostly to help us continue building our understanding of how RIOS works and secondarily because it would be quicker than rerunning the toolbox.

My sense is that the clipping option will work since I believe RIOS normalizes all the input layers, meaning that it would again stretch the values in the clipped preprocessing outputs from low to high for just the values in the clipped area even though the files from which they were clipped would potentially have a larger range of values for places outside the clipped area. But not at all sure about that.

Hopefully that makes sense... and thanks for any guidance you can offer!



  • swolnyswolny Member, NatCap Staff
    One thing to consider is that the pre-processor uses flow accumulation and flow length calculations that sum up what's going on upslope and downslope of each point. So if the smaller area is not hydrologically independent from the larger area, then you may get different values between running the pre-processor on the smaller vs larger area.

    That said, if the areas are not independent, I'd say that it's better to take into consideration the larger watershed, as then you're accounting for all (or at least more) upslope conditions above each point and all downslope conditions going to the stream.

    ~ Stacie
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