Hi InVEST users,
I’m working to evaluate the ES of one province by SDR, but the result are extremely high, and I still can’t find the reason after checking all the input data.
Could anybody help me out here, please?
Thank you!
Hi @chai ,
Thanks for your question.
While I agree that the USLE values visible in your screenshot appear to be high, please recall that they represent annual tons of eroded sediment summed within each watershed, so the values are very dependent on the sizes (total areas) of these catchments.
Additionally, as stated in the User Guide, “If the model has not been calibrated, only relative results should be used (such as an increase of 10% [from baseline under a a development scenario]) not absolute values (such as 1,523 tons)”. If you have observed data against which to calibrate and validate the SDR model results, we recommend attempting multiple runs with different parameter values. It may make sense to vary the usle_c and usle_p values in your biophysical table for some land cover classes, or to change the Borselli k parameter (kb) which the model is quite sensitive to, or try varying IC0.
It is difficult for us to diagnose what might be driving the seemingly high values by only looking at your screenshot. Please upload your logfile if you would like further assistance assessing these results.
-Jesse
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