Kc crop coefficient for urban and mining land cover classes

Science & Research
#1

Hello,
I am running the water yield model for a river basin in Brasil and I’m having trouble finding the most correct Kc (crop coefficient) value for land use classes such as urban area and mining area. I understand that the manual indicates a value of 1 for classes with no information, but a Kc =1 for urban or mining areas is not correct as far as I know.

I would like to know if anyone had ever had this issue and what Kc value should I include for pixels of urban and mining areas?

Thank you,
Julia

#2

Hi @JuliaNiemeyer,
Questions about Kc values come up frequently and there are already multiple threads on this subject, for instance Kc Values for Urban land use and Urban cooling queries about parameterization. If you’ve looked through those and still have questions, feel free to follow up!

#3

Hello,
Thank you for your reply. I saw both queries before adding mine. None of the previous gave any answers.
I tried to use the Kc calculator but it is written for urban classes: “for urban land classes, the monthly Kc values should reflect the percent of the urban area that is impervious surface. For example, for an urban area with 50% impervious coverage, the user could average the value for bare soil or impervious surface (evaporation only) by the natural vegetation class that most closely matches the natural vegetation within urban pixels (forest vs. grass).”
Since I have a large area that comprises very different vegetation types, this is not feasible. I would prefer stating that urban areas have ~100% impervious coverage. Still, I don’t know the Kc value for that. A more generic value would suffice, since I am working with a large region. Is there any information on that?
Usually in Brazil the Kc value is set to 1 for all land use classes. This is, as far as I know, the first research in which someone tries to gather specific kc values for each LU to run inVEST.

Thank you,

#4

Hi @JuliaNiemeyer,

I have asked the science team about this and haven’t gotten a lot of feedback yet (please see the latest post here). It sounds like some people have come up with values that work, but they may not be citable, peer-reviewed sources. For the mining areas, I would guess that’s mostly bare ground. Googling for bare soil Kc values did turn up some sources, but I can’t speak to their quality.

Since I have a large area that comprises very different vegetation types, this is not feasible.

Do you mean that each pixel covers a large area? Or that within each urban land class, there are too many different vegetation types? If there is that much variation within the urban land class, I would see if you can split it into multiple classes according to the amount/type of vegetation present, if any.

I’m sorry we don’t have a straightforward answer for you, and thanks for working to improve the quality of data available for Brazil!

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