Mountain Rivers and Incised Channels - River Dynamics and Integrated River Management - page 171

Figure 3.54 shows a landslide dam, the beautiful quake lake, and vegetated step-pool system on the
dam of the Jiuzhai Creek. The Jiuzhai Creek has become the most attractive tourist destination in Sichuan.
The landslide dams and quake lakes created multiple habitats for riparian and aquatic ecology. Different
physical conditions support different bio-communities, and diversified physical conditions may support
diversified bio-communities. The landslide dams and quake lakes in the Jiuzhai Creek provide
diversified habitats for different species and have the best ecosystems. Samples of benthic invertebrates
were taken from the Jiuzhai Creek and 60 other mountain streams in China. The Jiuzhai Creek is among
the best mountain streams, which have the highest taxa richness and high abundance.

(a) (b)

Fig. 3.54 (a) A landslide dam and a quake lake on the Jiuzhai Creek; (b) Beautiful vegetation on the landslide dam

3.4.2.3 Incision Control with Structures
The simplest form of an incision control structure consists of non-erodible material across the channel to
form a hard point. These structures are often referred to as rock sills, or bed sills. These types of
structures are generally most effective in small stream applications and where the drop heights are
generally less than about 1 m. A series of rock sills, each creating a head loss of about 0.6 m, was used
successfully on the Gering Drain in Nebraska (Stufft, 1965). The design concept is shown in Fig. 3.55.

Fig. 3.55 Channel stabilization with rock sills (after Whittaker and Jaeggi, 1986)