Mountain Rivers and Incised Channels - River Dynamics and Integrated River Management - page 144

from upstream. There is no step-pool system in the Jiangjia Ravine, as shown in Fig. 3.23(c). The
Xiaobaini Ravine flows into the Xiaojiang River from the opposite side (left side) and is 8 km from
Shengou Creek. Bed load motion and suspended load transportation are present in the stream. The bed
sediment consists mainly of gravel and sand. Although it has the same climate and bed sediment
composition as Shengou Creek, no step-pool system is present in the ravine, as shown in Fig. 3.23(d).
Shatford Creek is an eastward flowing tributary of Shingle Creek, in the Okanagan Valley of British
Columbia, Canada. Zimmermann and Church (2001) investigated the creek and reported the features of
step-pools in the creek. Four sections were selected each about 60 m in length. In each reach steps reflect
the location of key boulders. Figure 3.24 shows the longitudinal profiles of these reaches. Reach 1 is
dominated by rapids and lacks large boulders, therefore, the peak-flow water line is more linear in Reach
1 than in any of the other reaches (Fig. 3.24(a)). Reach 2 has a highly variable bed profile. At the 19-m
point of the reach, the channel is split around a large tree and a few large boulders and at the 32-m point
the channel goes through a tight bend, as shown in Fig. 3.24(b). Reach 3 is the steepest and has the
narrowest channel, largest boulders, and lowest mean velocity (Fig. 3.24(c)). Reach 4 has the clearest,
continuous set of step-pools. However, the heights of the steps and depths of the pools are highly
variable (Fig. 3.24(d)). The step at the 23-m point of the reach is composed of two large boulders, about
2 m in diameters each, which rest beside each other.
Fig. 3.24 The longitudinal profiles of four reaches of Shatford Creek British, Columbia, Canada. (a) Poorly
developed step-pool system in Reach 1 because of lacks large boulders; (b) Highly variable bed profile in Reach 2;
(c) Steepest and narrowest channel in Reach 3 with a developed step-pool system; (d) Clearest and continuous set of
step-pools in Reach 4
Rosport (1997) reported that the length of a regular step-pool system increases with the average
discharge. Whittaker (1987) suggested that the length of a regular step-pool system, or the distance