Purpose of buffer distance in pre-processing toolkit

Hi there,

I have two questions!

1. Could someone explain what the Riparian buffer distance input values (in the pre-processing tool) are used for? I am trying to create scenarios that limit riparian buffer protective actions to areas within 10m or 30m of rivers, and that take into account the effect of the change in buffer width on sediment/pollutant retention. I am doing this by changing the values of the coefficients in the biophysical table depending on whether I'm running a 10m or 30m buffer scenario and using a restricting layer in RIOS. So I want to check what the pre-processing buffer values do, incase they make changes to the biophysical coefficients...and if so, what these changes are.

2. When I use the 10m and 30m buffer shapefiles as a restricting layer in RIOS, I get bizarre outputs from RIOS. Any ideas on what might be the problem, or on other ways to force activities into 10m (or 30m) river buffer zones?

Thanks.
Sarah

Comments

  • swolnyswolny Member, NatCap Staff
    Hi Sarah -

    The riparian buffer distance in the pre-processor is used along with the retention coefficients to see how good the riparian vegetation is at retaining sediment/nutrient/etc before it hits the stream. It will create a relative ranking of the riparian zone, where high values of riparian index indicate places with high retention ability. The pre-processor does not change your input biophysical coefficients, but does use them.

    What do you mean by 'bizarre outputs'? If you want riparian activities to only happen within 10 or 30m riparian zones (and not at all outside of them), you can make a 'prevent' layer that covers all of the landscape that's outside of the riparian zone. This will tell RIOS that riparian activities can not happen outside the riparian zone. If you make a 'prefer' layer that covers the riparian zone, RIOS will first select pixels inside of these polygons, but it can also go outside of the riparian zone if it runs out of pixels to choose inside.

    ~ Stacie
  • Hi Stacie,

    Thanks for your response. Bizarre outputs in that only a sliver of the catchment is proposed for riparian buffer management activities. Good news is that your suggestion of using a prevent layer resolved this - so thanks!

    Sarah

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