Water yield model: Kc values for bare soil and roads

Hello All,

I just need a two advices for the biophysical table in the water yield model:

1) About Kc for bare soil. Can I use the value of Kc for bare soil as 0.2 (as in the biophysical_table in the sample dataset)?

2) About Kc for roads. In my LULC map road class is a combination of primary and secondary roads, so I just need one value. Now, in the sample data set there are two values: primary roads Kc=0.2 and secondary roads Kc=0.1. For my model can I just average these two values (0.15)?.  

Using these values (bare and roads) directly from your sample data set can affect in any way my results considering that my research area is in the tropics (South America) and I guess your biophysical table was develop for temperate areas (not sure)?

Thanks you very much for any help/comment/suggestion/etc,



  • swolnyswolny Member, NatCap Staff
    Hi Danka -

    We really don't recommend using the terrestrial sample data tables for your own work, it was created a long time ago and we have no information on where the values came from, they are only intended to give you something to run the model with initially.

    It is best to do a literature search to look for values that are more tailored to your area, or at least find global average values from a known source.

    ~ Stacie
  • Hello Stacie,

    Ok, I'll use other values based on literature. 
    I have another question about the biophysical table. I have to evaluate current condition (2010) and future condition (2040). I have four future scenarios with different urban sizes and road lenght depending on the specific scenario. I'm calculating Kc for urban areas using this equation in the user guide: f*0.1+(1-f)*0.6 where f=fraction of impervious cover and I'm not sure how to calculate KC for roads (any help is appreciated).  
    The question is: do you think that I have to generate different biophysical tables?: one table for current conditions (with Kc values for urban and roads in 2010) and four tables for future conditions (with Kc values for urban and roads in 2040 adjusted for each scenario).   OR can I simply produce only one biophysical table (using the same values of Kc for urban and roads in 2010) and use it for both current and future conditions?

    Thank you very much for any help,
  • PerrinePerrine Moderator, NatCap Staff
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