Page 249 - Handbook of Gold Exploration and Evaluation

220 Handbook of gold exploration and evaluation

4.14 Channel classification based upon patterns and styles of sediment load
(from Miall, 1985).

· `Stage'. The heights of free surface of flow above a given datum in a river
channel, usually the lowest point of the bed.
· `Top width'. Width of the channel section at the free surface.
· `Water area A'. Cross-sectional area of flow normal to the direction of flow.
· `Wetted perimeter P'. Length normal to the direction of flow along the line
of intersection of the channel-wetted surface.
· `Hydraulic radius R' is given by R ˆ A=P.
· `Hydraulic depth D' is given by D ˆ A=T.
· `Section factor Z' for critical flow computation is the product of the water
ÿ2
depth and the square root of the hydraulic depth given by Z ˆ AD .

Table 4.4 Channel classification (after Rust, 1978)
Sinuosity Single channel Multiple channel
B.P. < 1 B.P. > 1
Low < 1.5 Straight Braided
High > 1.5 Meandering Anastomosing