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Use of Surrogate Models To Estimate Suspended Sediment 25
Table 4. Comparison of suspended sediment loads during selected storm events estimated using acoustic backscatter and sediment-transport curves based on
2008–10 streamflows in the Clearwater River at Spalding, Idaho, and Snake River near Anatone, Washington.
[Abbreviations: ABS corr
, acoustic backscatter corrected for beam spreading and attenuation by water and sediment in decibels (dB); na, not applicable]
Site
Event
No.
Event dates
Sediment load for ascending limb of hydrograph
(tons)
3-MHz_ABS corr
or 1.5-
MHz_ABS corr
model
2008–10
sediment
transport curve
Percent
difference
Sediment load for descending limb of hydrograph
(tons)
3-MHz_ABScorr or
1.5-MHz_ABS corr
model
2008–10
sediment
transport curve
Percent
difference
Clearwater River na na – All 7 events combined 172,000 148,000 -15 131,000 178,000 30
1 May 13–24, 2008 59,400 56,700 -5 13,000 18,800 36
2 November 12–30, 2008 2,070 1,120 -60 3,750 2,850 -27
3 January 1–12, 2009 2,950 790 -116 3,540 2,700 -27
4 April 21–May 1, 2009 13,000 12,900 -1 17,700 24,600 33
5 May 18–June 12, 2009 9,130 8,170 -11 51,100 62,600 20
6 May 14–26, 2010 14,700 11,200 -27 7,370 10,200 32
7 June 2–July 5, 2010 70,600 57,200 -21 34,900 56,000 46
Snake River na na –All 6 events combined 585,000 409,000 -35 762,000 1,260,000 49
1 April 18–May 3, 2009 122,000 68,500 -56 89,600 113,000 23
2 May 5–11, 2009 48,600 39,400 -21 24,400 31,200 24
3 May 18–24, 2009 98,400 84,100 -16 106,000 129,000 20
4 April 20–27, 2010 15,700 11,300 -33 12,100 15,300 23
5 May 16–30, 2010 33,000 26,600 -21 48,400 73,000 41
6 June 2–19, 2010 267,000 180,000 -39 481,000 895,000 60