Methods to Estimate the Total Sediment Transport Capacity in Irrigation Canals - Sediment Transport in Irrigation Canals: A New Approach - page 232

A.2 ACKERS AND WHITE METHOD

The method as developed by Ackers and White (1973) is based on flume
experiments with sediment with a uniform or nearly uniform size distri-
bution, with fully established flow conditions including bed forms, for
water depths smaller than 0.4 m and for flows in the lower flow regime
with Fr < 0.8. The method uses three dimensionless parameters, namely
the grain size sediment parameter D ∗ , the mobility parameter F gr and the
transport parameter G gr to describe the sediment transport.
- The grain size sediment parameter D ∗ reflects the influence of gravity,
density and viscosity:

( s 1 / 3

− 1) g

ν 2

D ∗ = d 35 (A.1)

- The mobility parameter F gr is the ratio of the shear force on a unit area
of the bed to the immersed weight of a layer of grains. The equation for
the transitional range (1 < D ∗ < 60) is:

⎡ ⎤

1 − n

u n
∗

V
√ 32 log 10 h

⎣ ⎦

F gr = gd 35 ( s

d 35

(A.2)

− 1)

with:
n (A.3)

- The transport parameter G gr is based on the stream power concept and
the equation reads:

= 1 . 00 − 0 . 56 log D ∗

c F gr 1 m

G gr =

A −

(A.4)

with

0 . 23
√ D ∗ + A = 0 . 14 (A.5)

9 . 66
D ∗

m = + 1 . 334 (A.6)

(log D ∗ ) 2 log c = 2 . 86 log D ∗ − − 3 . 53 (A.7)

The Ackers and White function for the total sediment transport
reads as:

G gr νd 35 V
u ∗

n

q s = (A.8)

where:
D ∗ =

grain parameter (dimensionless)

d 35 = representative particle diameter (m)