This is the results that i got after the running InVEST SDR version 3.7 model, I want to know what is the meaning of above table mentioned in last row Watershed result . Is that meaning average result of total watershed area or what else
Hi @Nayanathara -
This table was not created by the InVEST model, so I can’t say exactly what went into these calculations.
The model does produce a table with the total (summed) soil loss (USLE) and sediment export per watershed/sub-watershed provided as input. I’m guessing that’s the data in your table given by Watershed ID, and it does have values of tons/watershed/year. If you add up the sed_export or USLE values for all of the sub-watersheds in a watershed, then you should get the total amount produced in the whole larger watershed, also in tons/watershed/year. The values provided by the model are totals/sums, not averages.
Also a reminder that the sediment retention value should be used as a relative index only (given values of low->high), it does not represent the actual amount of sediment retained from upslope.
how do we convert the tons/watershed/year to tons/ha/year?
Thanks for your question.
To convert from tons/watershed/year to tons/ha/year, simply divide the tons/watershed/year results by the area (in hectares) of each respective watershed.
From the table in the image above (column 1 = Watershed ID, … column 8 = Total soil loss (t/ha/yr):
(column 7) / (column 2) = column 8