LEC 8

Question 1

A naturally occurring material that is broken down by processes of weathering and erosion

Answer 1

sediment

Question 2

sources of sedimentation (LUIAMO)

Answer 2

land clearing
unsealed roads
in-stream disturbance
agricultural activity
mining
other activities

Question 3

primary clay, primary silt, small aggregate, large aggregate, primary sand

Answer 3

particle classes

Question 4

distribution of classes function of texture; diameter of small and large aggregates function of texture

Answer 4

at detachment

Question 5

sediment enriched in fines

Answer 5

after deposition

Question 6

grains rolling, sliding and/or saltating (hopping) in frequenr or continuous contact with bed

Answer 6

bedload

Question 7

transport of sediments by hopping and bouncing along the channel bed

Answer 7

saltation

Question 8

grains in suspension above the bed for extended periods of time

Answer 8

suspended load

Question 9

that part of suspended load that is not found on the bed

Answer 9

wash load

Question 10

the coarse fraction normally found in the bed

Answer 10

bed material load

Question 11

under ______, the rate of sediment upward flow due to turbulent diffusion is equal to the downward flow rate due to the settling action of gravity

Answer 11

steady state condition

Question 12

taken at fixed depths from the river bottom

Answer 12

depth-integrated or point sampling

Question 13

the relative quantity collected at any depth is in ____ to the velocity at that depth

Answer 13

proportion

Question 14

the ratio of the dry weight of sediment to total weight of the sample is the ___

Answer 14

sediment
concentration

Question 15

is also used to
estimate the sediment loads on days when no measurements are available

Answer 15

rating curve relating suspended-sediment discharge and water discharge

Question 16

the rate at which the capacity of a reservoir is reduced by sedimentation depends on

Answer 16

the quantity of sediment inflow
the percentage of this inflow trapped in the reservoir (trap efficiency)
the density of the deposited sediment

Question 17

the volume occupied by the sediment in the reservoir will depend on the ____ of
the deposited material

Answer 17

specific weight

Question 18

if a mixture of materials is present in the sediment, a ____
should be calculated

Answer 18

weighted average specific weight