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I got the result of SDR model sediment retention + sediment export are not equal soil loss

srichaichanasrichaichana Member
edited September 2018 in Freshwater Models
Dear, All
I got the result from SDR model. Show in the table (case I and II)  below and I can summaries in soil loss not equal with soil retention plus sediment export.

For common, Soil loss = sediment retention + sediment export.   
I try adjust the value of variable such as threshold flow accumulation, Borselli k Parameter, Borselli IC0 parameter and max sdr value. I try to run SDR model for many time for balancing the Soil loss = sediment retention + sediment export. 


Best regard,
Jamroon 

Case I

Watershed IDSoil retentionSediment exportSoil lossSoil retention + Sediment exportDifference from soil loss
1      23,467,664.06      1,143,645.55      29,501,314.72      24,611,309.614,890,005.11
2        5,876,654.90         561,454.43      15,088,227.44         6,438,109.338,650,118.11
3      11,845,529.00         860,033.25      20,156,820.06       12,705,562.257,451,257.81
4      13,033,760.25         879,720.54      18,155,095.25       13,913,480.794,241,614.46
5      27,802,141.39         965,320.45      24,060,954.69        28,767,461.84(4,706,507.15)
6      39,222,794.06      1,088,151.07      27,070,598.78        40,310,945.13(13,240,346.35)
7      18,280,559.38      1,025,882.28      21,939,762.25         19,306,441.66    2,633,320.59
8      31,006,976.12      1,652,715.18      40,979,857.66         32,659,691.30    8,320,166.36
9      50,652,542.20      1,257,778.08      32,286,226.00         51,910,320.28(19,624,094.28)
10        4,368,798.50         353,256.88      13,067,254.44           4,722,055.38     8,345,199.06
Total   225,557,419.86      9,787,957.71    242,306,111.29        235,345,377.57     6,960,733.72


Post edited by srichaichana on

Comments

  • swolnyswolny Member, NatCap Staff
    Hi Jamroon -

    For this simplified model, sediment export + sediment retention will generally not equal soil loss from a pixel, because of the way that sediment retention is calculated. The User Guide says this about sediment retention: "...represents the avoided soil loss by the current land use compared to bare soil, weighted by the SDR factor. This index underestimates retention since it does not account for the retention from upstream sediment flowing through the given pixel. Therefore, this index should not be interpreted quantitatively. "

    ~ Stacie

  • @swolny Thank you so much.
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