Units of SDR model results

Dear InVEST users and experts,

In the user guide, the unit for SDR results is either tons/pixel or tons/watershed. However, in many papers ton·ha−1·yr−1 has been used. Which one is correct? ton·ha−1·yr−1 or tons/pixel for sediment export and soil erosion?

The unit is tons/watershed, it is rational for a watershed. Those units in the papers as ton·ha−1·yr−1 has Benn converted from the original result of the Model.

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Thank you, but in the user guide the unit for USLE is ton·ha−1·yr−1 and tons/pixel. It confused me.

Hi @marye_belete -

As @hilu202 said, the USLE and sediment export results from the model have units of tons/pixel. This can be easily converted to tons/ha, based on the size of the pixel, and we often do this when post-processing model results.

~ Stacie


@swolny To get the Total soil loss in (t/yr) for sub-watersheds, do we first convert the USLE output (t/pixel/yr) to (t/ha/yr), and then use zonal statistics tool to get the sum of each watershed which will be (t/yr)?

Yes @Nametso, that’s a good way of getting the total USLE/soil loss for each sub-watershed.

~ Stacie

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