Dams and Impounded Rivers - River Dynamics and Integrated River Management - page 445

the reservoir rapidly in the first two years (2003-2005) following impoundment, but from 2005 to 2007,
the amount of sedimentation in the reservoir remained relatively constant. Comparing with the calculated
sedimentation volume, the measured sedimentation volume in the first 4 years of operation was much
less. The main reason was a dramatic sediment load reduction since the 1980s (Liu et al., 2008).
Fig. 7.42 Measured cross sections at the Three Gorges Reservoir in 2003, 2005, 2006, and 2007 at 5.6 km (a), 160 km
(b), and 356 km (c) from the dam, respectively (MWR, 2008)
7.4.2.2 Sedimentation in the Fluctuating Backwater Region
The fluctuating backwater region is the river reach with a flood stage between the FCL and NPL, as shown
in Fig. 7.38. The industrial hub of Chongqing is in the fluctuating backwater region, which is located at
the confluence with the Jialing River—a major tributary of the Yangtze River. There is a passenger ship
harbor—Chaotianmen Harbor and a freight ship harbor—Jiulongpo Harbor in Chongqing. The Chaotianmen
shipping terminal at Chongqing is about 602 km from the dam, any small errors in the computation of the
hydraulic gradient will result in sizable differences in stage elevations.