Integrated River Management - River Dynamics and Integrated River Management - page 744

2008 and 2009 (Zhang et al., 2010). The rivers and measurement stations are shown in Fig. 11.28.
Because the step height and step length are not regular, J S cannot be directly measured. The development
degree of the step-pool system, S P , was used to reflect the effect of the step-pool system on the flow and
bed load transportation. The rate of bed load transport per width of channel g b , the stream power p , and
the development degree of step-pool system S P were measured at these stations. The rate of bed load
transport was measured with a double box sampler, as shown in Fig. 11.29. The outer box was installed
into the stream bed with its top edges even with the local bed surface. The size of the inner box was
0.5m×0.2m×0.2m. A steel-wire mesh was used at the bottom of the box to drain the water rapidly when
the box was lifted out of the river. Wet weight of the collected bed load sediment was measured and the
rate of bed load transport was calculated.

1

Yinmin

Yangtze Ri ver

0 10 20 30km

Xiniutang

Red Soil

Kuaihe R.

Lumao

Kuaihe

ĺ

Ĺ

ľ

Ľ

ķ

ļ

Awang

Dabai R.

Ļ

City
Town
Measurement section

ĸ

Dongchuan City

Gongshan M ajia

Ļ Xiaohaihe R. ļ Shengou Creek Ľ Qingshui Gully ľ Hunshui Gully ķ Awangxiaohe R. ĸ Ĺ Xiaobaini R. ĺ

Dabaini R.

Taojiaxiaohe R.

Fig. 11.28 Measurement stations on the tributary streams of the Xiaojiang River (in the upper Yangtze River basin)

Fig. 11.29 Double box sampler of bed load

The development degree of the step-pool system, S p , was defined in Chapter 3 and was measured with
a specifically designed instrument shown in Fig. 3.28 and the value of S p is calculated with Eq. (3.5). The
energy slope resulting from bed structures, J P , cannot be directly measured. Nevertheless, J P may be
represented by the measurable value of S p . The larger is the value of S p, the higher the energy slope
resulting form bed structures J P . Although the energy slope resulting form bed load motion is given by
Eq. (11.7), the energy slope resulting form bed load motion, J b , is not measurable as well, but is represented
by the rate of bed load transport per width g b . The higher is the rate of bed load transport, the larger is the
energy slope resulting from bed load motion, J b .
Figure 11.30 shows the Chaqing Gully, which flows into the Jiangjia Ravine, and the Hunshui Gully;
which flows into the Daqiao River. The Jiangjia Ravine and the Daqiao River are both tributaries of the