Encyclopedia of Environmental Science and Engineering, Volume I and II

1076 SEDIMENT TRANSPORT AND EROSION

and f s depends on the cohesiveness of the material in the

channel banks. For example, f s is approximately 0.1, 0.2, and

0.3 for low, medium, and high cohesiveness respectively.

The data of Lacey and Blench were mainly from canals,

with moderate to low sediment loads ( c  500 ppm) and

with sand beds and slightly cohesive banks.^17

Simons and Albertson 44,21 have extended the regime

equations to make them applicable to the five channel clas-

sifications shown in Table 4.

They proposed the following general equations:

P  K 1 Q^1 
^2 (47)

101

101

102

102

104

104

103 105 106

103

SEDIMENT LOAD (tons/day)

MEAN DAILY DISCHARGE (cfs)

SUMMER STORMS AND

WINTER RUNOFF

SNOW RUNOFF

FIGURE 13 Typical sediment rating curve (adapted from Ref. 38).

Q

Q Qs

t

SUSPENDED

SEDIMENT

LOAD

Qs

DISCHARGE

FIGURE 14 Variation of sediment load with time (adapted from Graf).

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