Table 3 Accumulated sediment in the basin plain within the last 15 years derived from seismic (A) and gauging data (B)

A) Seismically derived

 Mean sedimentation rate

0.03 m/yr

 Total basin plain area

5.05 × 10⁶ m²

 Mean sediment accumulation within 15 yrs

15 yr × 0.03 m/yr

 = 0.435 m

 Sediment volume

0.435 m × 5.05 × 10⁶ m²

 = 2.2 × Mio m³

 Sediment dry mass in 15 years (incl. event deposits)

1855 kg/m³ × 2.2 Mio m³

 = 4.08 Mio t

B) Instrumentally derived (suspended load)

 Avg. river input: within 15 years: 2005 flood input:

(Bezzola & Hegg, 2007)

0.302 Mio. t yr⁻¹

15 yr × 0.302 Mio. t yr⁻¹

 = 4.53 Mio. t

0.42 + 0.59 Mio. t

 = 1.01 Mio. t

 Total river input:

4.53 + 1.01 Mio. t

 = 5.54 Mio. t