Plant available water content

Is available water supply (0-20, 0-150cm), in SSURGO data, a plant available water content for that specific layer depth? Can we directly use this available water supply data for the annual water yield model of the US watersheds? The numbers look different from the available water content in the SSURGO, so I assume the available water supply can be used directly in the model. Any suggestions?

Hi @JackR -

If you’re using the Soil Data Development Toolbox, it has an option for Available Water Capacity, which is what you want. It’s in units of cm/cm, a fraction which is appropriate for the model, while Available Water Supply has units of cm, and is considered a volume. Use the whole depth range (0-200cm), and I usually use an Aggregation Method of “weighted average”, but it would be worth seeing how different “dominant component” is.

If you’re not using the Toolbox, and don’t see Available Water Capacity in the database, I’m not sure what to do. Perhaps they calculate AWC on the fly in the toolbox, so you could find out how they do that calculation.

~ Stacie