Debris Flows and Landslides - River Dynamics and Integrated River Management - page 251

(a) (b)
Fig. 4.79 (a) Agriculture and village on a landslide deposit by the Xiaojiang River; (b) The Dongchuan city town
on a huge landslide deposit in Yunnan, China (See color figure at the end of this topic)
Debris flows transport a huge amount of sediment to the gully mouths, or confluence with rivers. In
general the rivers have much smaller bed gradient than the debris flow gullies. Therefore, most of the
sediment can not be carried downstream by the river flow and rather deposits at the gully mouth to form
debris flow fans. Figure 4.80 shows a debris flow fan at the Awangxiaohe Ravine, which flows into
the Xiaojiang River. The Awangxiaohe Ravine was a debris flow gully. The debris flow fan is flat and
fertile. Local people have reclaimed the land for agriculture and township construction. Nowadays, the
Awangxiaohe town has becomes a center for residence, education and market.
Fig. 4.80 A new town developed on the Awangxiaohe debris flow fan in the Xiaojiang River basin (See color figure at
the end of this topic)