3.3 Measurement of suspended sediment concentration (SSC)
Except near the riverbed, mixing of suspended sediments streams is
fairly homogenous throughout the cross-section. Thus, collection of
water samples was done at a turbulent section to allow vertical and
horizontal mixing of sediments. The sampling bottles were fully
submerged and capped when fully filled. Three 500 ml water samples were
collected per sampling event. Each bottle of water sample was filtered
using 0.45 µm pore size, 47 mm-diameter Whatman nylon membrane filters,
and a Nalgene vacuum pump and filtration unit. The filter papers were
air-dried for three days in the field to remove moisture before being
individually stored in aluminium foil and resealable plastic bags. Then,
suspended sediment mass was obtained in the laboratory by weighing the
dried samples. The average mass of suspended sediment per sampling event
(mg/500ml) was multiplied by 2 to obtain the average SSC in mg/L.