Water Environment

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The Fluvial Changes of Jingjiang Reach during the
Preliminary Period of the TGP Operation
HUANG LI
Changjiang River Scientific Research Institute of
Changjiang Water Resources Committee
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content
1 Introduction
2 calculation analysis
3 field data analysis
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1 Introduction

• Jingjiang is the major reach in the middle and
  lower reach of Changjiang river.Jingjiang reach
  is 347.2km.
• The upper Jingjiang is presently about 171.7km
  long from Zhicheng to Ouchi-mouth,and is a
  slightly curved fork river type.
• The lower Jingjiang is about 175.5km long from
  Ouchi-mouth to Chenglingji, and is typical of
  sinuous stream.

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Upper-Jingjiang reach
Lower-Jingjiang reach
Middle reach of Changjiang river,955km long
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The schematic diagram of the upper Jingjiang reach
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The schematic diagram of the lower Jingjiang reach
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2 calculation analysis
Main conclusions (1)

• at the end of the twentieth year,the river reach
  from Yichang to Chenglingji will be scoured,the
  quantity will be 17.97108 t and about 13.31108
  m3.
• The scouring intensity increased gradually along
  the river reach.
• The erosion above Taiping-mouth will reach an
  equilibrium approximately.

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Table1 Accumulated deposition-erosion amounts
from Yichang to Chengliji
item year Yichang- Chenglingji Yichang- Songzikou Songzikou- Taipingkou Taipingkou- Ouchikou Ouchikou- Chenglingji
Deposition-erosion volume (108m3) 2007 -4.8 -0.52 -0.98 -1.88 -1.42
Deposition-erosion volume (108m3) 2012 -7.68 -0.52 -0.98 -3.43 -2.76
Deposition-erosion volume (108m3) 2022 -13.31 -0.53 -0.98 -3.75 -8.05
Deposition-erosion weight (108t) 2007 -6.48 -0.7 -1.32 -2.54 -1.92
Deposition-erosion weight (108t) 2012 -10.37 -0.7 -1.32 -4.62 -3.72
Deposition-erosion weight (108t) 2022 -17.97 -0.71 -1.33 -5.07 -10.86
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Table2 Accumulated deposition-erosion areas
from Yichang to Chengliji

unitm2
year Yichang- Chenglingji Yichang- Songzikou Songzikou- Taipingkou Taipingkou- Ouchikou Ouchikou- Chenglingji
2007 1221 -687 -1609 -2176 -834
2012 1953 -687 -1609 -3970 -1622
2022 3385 -700 -1609 -4340 -4730
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Deposition-erosion amounts (104 m3)
Yichang-Songzikou
Songzikou-Taipingkou
Fig1 1-10 year deposition-erosion process from
Yichang to Chenglingji
Taipingkou-Ouchikou
Ouchikou-Chenglingji
The years after the TGP operation
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Deposition-erosion amounts (104 m3)
Taipingkou-Ouchikou
Ouchikou-Chenglingji
The years after the TGP operation
Fig2 11-20 year deposition-erosion process from
Taipingkou to Chenglingji
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Main conclusions (2)

• At the end of year 2009,the main river channel of
  the upper Jingjiang reach will be scoured
  3.71108 ton when the discharge in Yichang is
  5500m3/s,and the lower Jingjiang reach, 2.16 108
  ton.
• At the end of year 2022,the upper Jingjiang
  reach, 4.88 108 t,the lower Jingjiang reach,
  8.05 108 t.

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Elevation (wu song,m)
Distance from the dam (km)
Fig3 Changes of the thalweg from Yichang to
Chenglingji after the operation of the TGP
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Elevation (wu song,m)
Distance from the dam (km)
Fig4 Changes of the thalweg from Yichang to
Chenglingji after the operation of the TGP
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Main conclusions (3)

• Because of the scouring from Yichang to
  Chenglingji,the relation between water level and
  the discharge will change correspondingly.For the
  mid and lower river discharge the water level
  will descend to some extent.

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Table3 The decrease of water level
after the operation of the TGP (compared to
2003) (m)
Shishou
Yichang
Discharge (m3/s) At the end of 2006 At the end of 2009 At the end of 2022
5500 0.42 0.63 0.91
10000 0.40 0.60 0.84
20000 0.33 0.54 0.80
30000 0.26 0.44 0.68
40000 0.17 0.32 0.56
50000 0.14 0.24 0.47
Discharge (m3/s) At the end of 2006 At the end of 2009 At the end of 2022
5500 1.07 1.70 2.64
10000 1.09 1.63 2.39
20000 0.68 1.22 1.94
30000 0.53 0.99 1.50
40000 0.33 0.86 1.39
Jianli
Shashi
Discharge (m3/s) At the end of 2006 At the end of 2009 At the end of 2022
5500 0.60 1.16 1.73
10000 0.89 1.36 1.91
20000 0.58 0.96 1.58
30000 0.50 0.79 1.20
40000 0.10 0.37 0.55
Discharge (m3/s) At the end of 2006 At the end of 2009 At the end of 2022
5500 0.81 1.51 2.39
10000 0.83 1.49 1.90
20000 0.55 0.86 1.33
30000 0.34 0.57 0.89
40000 0.16 0.34 0.56
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3 field data analysis

• Field data analysis from hydrological bureau of
  Changjiang Water Resources Committee show
  that,after TGP is put into operation in June
  2003,the downstream of the TGP dam from Yichang
  to Chenglingji have occurred a long-distance
  erosion.

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Table4 the amounts of erosion from Yichang to
Chenglingji
Period of time (yearmonth) Yichang-Zhicheng Yichang-Zhicheng Upper-Jingjiang Upper-Jingjiang Lower-Jingjiang Lower-Jingjiang Yichang-Chenglingji Yichang-Chenglingji
Period of time (yearmonth) Erosion capacity Erosion intensity Erosion capacity Erosion intensity Erosion capacity Erosion intensity Erosion capacity Erosion intensity
2002.102003.10 0.3 500 0.21 130 0.52 300 1.03 250
2003.102004.10 0.2 340 0.46 290 0.61 360 1.27 310
2002.102004.10 0.5 840 0.67 420 1.13 660 2.30 560
Note Erosion capacity ( unite 108 m3)Erosion
intensity (unite m3/m )
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