Sediment Movement in Alluvial Rivers - River Dynamics and Integrated River Management

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the estuary and the neighboring coastal areas. It can be deduced that the remaining 0.2 billion tons is

transported into the ocean.

For the Yangtze River the main sediment yield area is the drainage area between Panzhihua to Yichang,

from Yichang to Datong is the sediment transportation channel, and from Datong to the river mouth is the

estuary. Equation (5.80) is the Yangtze River sediment matrix:

2.10

0.02

1.60

(5.80)

0.05

0.55

0.15

Yangtze

0.00

0.45

0.30

The explanation of the components is similar to that for Eq. (5.79).

Different rivers have different types of sediment matrix. For instance, a completely channelized river

has a pseudo-diagonal matrix, because all sediment comes from upstream and is transported through the

channel. There is no bank erosion and sedimentation on the channel bed.

Sediment matrix for channelized rivers

(5.81)

If the watershed is well-managed and there is no sediment yield from upstream reaches, the sediment-

starved flow will scour the channel bed and banks, and waves and tidal currents will cause estuary erosion. In

this case the sediment matrix becomes a lower triangular matrix, the Rhein River is an example of such a river.

Sediment starved rivers

(5.82)

Hyperconcentrated rivers have a matrix of the following type:

Hyperconcentrated rivers

(5.83)

The sediment matrix of the Yellow River is an example of this type.

River training engineering can be expressed with a matrix as well. For instance, a river suffering from

delta erosion has the sediment matrix as follows:

100

010

111

(5.84)

The inverse matrix of A is

100

010

111

(5.85)

Some engineering measures are taken to control coastal erosion in the estuarine area and make the

river channelized. The sediment matrix after the training will be

100

010

011

Channelized river matrix

(5.86)

River Dynamics and Integrated River Management

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