Rapid channel incision of the lower Pearl River (China) since the 1990s

X. X. Lu (1) , S. R. Zhang (1) , S. P. Xie (2) , P. K. Ma (2)

1 Department of Geography
2 Zhaoqing Hydrological Bureau of Guangdong Province

This paper reported a dramatic channel incision (>10 m in the deepest cut) during the past 10 years or so in the lower Pearl River, the second largest river in terms of water discharge in China. The channel incision had caused changes both in the channel geometry as well as in the river hydraulics. Also, the water exchange between the two major tributaries of the Pearl River, the Xijiang and Beijing, had been significantly changed due to the channel incision. The rapid channel incision was principally the result of extensive sand mining in the lower Pearl River and the delta region due to the booming economy in the Pearl Delta region. Slight increase of water discharge and significant decrease of sediment load since the early 1990s in both the Xijiang and Beijiang also likely contributed to the observed dramatic river bed donwcutting to some extent. This has important implications for river management, as the large Chinese rivers have seen a dramatic depletion of sediment fluxes due to the combined effects of declining rainfall, dam constructions, water diversion, reforestation and afforestation, and sediment mining over the recent decades.

Domaines: Interfaces continentales, environnement; Océan, Atmosphère; Sciences de la Terre

X. X. Lu, S. R. Zhang, S. P. Xie, P. K. Ma. Rapid channel incision of the lower Pearl River (China) since the 1990s. Hydrology and Earth System Sciences Discussions, 2007, 4 (4), pp.2205-2227. ⟨hal-00298859⟩