The On-going Eco-hydrological & Eco-hydraulicResearch Programsfor Improvement of Three Gorges Reservoir Operation

Liao Wen Gen
Department of Water Environment, CIWHRCONTENT• PART ONE — BACKGROUND– Three Gorges Project and Its Impacts– Restoration Measurements– Eco-hydraulic & Eco-hydrological needs• PART TWO — ON-GOING PROGRAMS– The effects of hydrological and hydrodynamicchanges caused by hydropower projects on important
living resources– Artifical Floods for the Spawning of “Four Major
Economic Fish”– Demands of Water Quality Protection of ThreeGorges Reservoir for the Improvement of damoperation1

PART ONEBACKGROUND

Yangtse River
9 Yangtse River ---- the largest river in China
9 34% water resources, 900 billion cubic meters waterdischarged into the Sea
9 19% land (24% plowland), 35% population, 37% GDP
in the basin
9 Most abundant bio-diversity zone in China

40%
35%

35%

37%
34%

30%
25%
20%

19%

15%
10%
5%
0%landpopulationwaterresources

GDP2

Three Gorges Project
9 The largest hydropower project in the world
9 The dam is 185 m, the total storage capacity is 39.3
billion m3, and the annual electricity generation is 84billion kilowatt-hours
9 To gain a great comprehensive benefit on flood control,hydropower generation and navigation improvement

Environemtal Impacts
9 Natural environment and social environment
9 Positive impacts, such as:z Substitute 50 million tons of coal annually, reducing
10 million tons of CO2, 1 million tons of SO2, andlots of other waste gases
z Prevent highly populated downstream area fromflooding

9 Negative impacts, such as:z Huge Migrationz Land submergencez River block and natural flow alterationz Habitat damage

3Measures for Yangtse River
Improvement and Habitat Restoration
Measures

Remarks

Nature reserve

12 nature reserves

Soil & Water Conservation
closed fishing seasons
Sustainable fishery mode
Pollution control
Eco-friendly dam operationongoing
Remarkable effects
Under researchbetter management needed
Important ,Under research………

We need eco-friendly dam operation!
Yes , but how?

Examples of Concerned Eco-hydraulic& Eco-hydrological needs

Example 1---- The Chinese Sturgeon
9 one of the rare and endangered aquatic
animals, known as a living fossil
9 used to migrate upstream into Jinsha
River for propagation.
9 After the construction of Gezhouba damin 1980, it takes the near downstream
water area as spawning site.
9 questions: (1) suitable hydraulicconditions for spawning? (2) How does
three gorges dam operation affectChinese sturgeon’s spawning?

4

Examples of Concerned Eco-hydraulic& Eco-hydrological needs

Example 2 ---- Eutrophication Control
9 nutrient contents are much higher
than standards
9 no “algae bloom” occurred before
9 since water level rises up to 135
meters in 2003, “algae bloom”
happens every year.
9 questions: (1) how does tributary
eutrophication respond to flow
conditions? (2) does flood
discharge restrain algae
accumulation in tributaries annually?

Alage bloom in a tributary（March, 2006)

Examples of Concerned Eco-hydraulic& Eco-hydrological needs

Example 3 ---- Four Major Economic Fish
9 Questions : (1) what is the appropriate
flow conditions for the “ four major
economic fish” habitat restoration? (2)how large and how long should anartifical flood be made to stimulate thefour major economic fish’s spawning?
403530252015105035.8721.54grass carp

Jianli Station

28.54

27.47

black carp

silver carp

19.04 194.06 3.39
1.05
1997 1998 1999 2000 2001 2002 2003 2004 2005

100 million 35.87 27.47 21.54 28.54 19.04

194.06

3.39

1.05

bighead carp

5

PART TWOONGOING PRAGRAMS– Program 1: The effects of hydrologicaland hydrodynamic changes caused byhydropower projects on important living
resources– Sponsored by: National Nature
Science Foundation of China– Research period: 2005—2008– Fund: 1.3 million Yuan

6

– Living Resources Objects of Research :Chinese sturgeon, four major economicfish– Hydropower projects: Three Gorges dam
and Gezhouba dam– Research Scope : reservoir + downstream+ river mouth = 2300 km or so– Research Goals• To understand the hydrological changesof Yangtse River• To clarify the water temperature
distribution changes along the river• To illustrate the eco-hydraulic conditions
for Chinese Sturgeon’s spawning• To assess the status of existing habitats
for four major economic fish7

– Technical Difficulties• Lack of long-term monitoring data,
especially for “four major economic fish”• Little knowledge of the life processes orcharacteristic phenomena of theconcerned living organisms– Methodology• History data analysis• Field monitoring• Laboratory study• Numerical modelingPrimary Results of Program 1– A Spatially Distributed Hydrological Model forYangtse River Basin– An eco-hydrological index system for Yangtse
River– Only when flood waters swell, “Four major
economic fish” spawn. Meantime, the Increasing
rates of Q and Z, flood swelling time, and intervalof floods affect the spawning scale– The number of days of flooding downstream ofThree Gorges dam should maintain 15-30 (fromApril to June annually) for keeping a normal
scale of spawning

Water Level(m)

Yidu

46

Spawning records
4544

Jianli43 31

Guangji
42 30 23

41 29 2240 28 21

27 20

26 19

18

17

Month.date 4.30

5.10

5.20

5.30

6.10

6.20

6.30

8

Primary Results of Program 1– The exact locations of Chinese
Sturgeon spawning sites: up spawning
site and lower spawning site
– the hydrodynamic characteristics ofChinese Sturgeon spawning sites:
moderate bottom velocity(1-2m/s),
vertical upwards velocity– Since Three Gorges reservoir began tostore water, the spawning time ofChinese Sturgeon trends to delay by 20days– Program 2: Artifical Floods for theSpawning of “Four Major Economic Fish”– Sponsored by: China Three Gorges
Project Corporation– Research period: 2006—2008– Fund: 1.1 million Yuan
– As a supplement to Program 19

– Living Resources Objects of Research :four major economic fish
– Hydropower projects: Three Gorges dam– Research Scope : downstream +upstream + Han River– Research Goals• To understand the response of fourmajor economic fish’s spawning tohydrological changes• To assess the possibility of four majoreconomic fish’s spawning in the near
upstream waters of Three Gorges
reservoir• To provide eco-hydrological data formaking “artifical floods”

10

– Research Progress• Field investigation• Yangtze River suffers rare drought inflood season in 2006

– Program 3: Demands of Water Quality
Protection of Three Gorges Reservoir for
the Improvement of dam operation– Sponsored by: China Three Gorges
Project Corporation– Research period: 2006—2008– Towards tributary “algae bloom”
control

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– Research Goals• To find out the relationship between “algaebloom” and hydrodynamic characteristics
in the tributaries of Three Gorges reservoir• To understand the needs of tributary flow
adjustment for water quality improvement• To study the feasibility of tributary flow
adjustment and put forwards suggestions– Research Scope : Typical Tributaries• Xiangxi River: phosphorite production zone
• Daning River: tourist attraction• Zhushan River: urban river
Xiangxi river basin
Xiangxi River

Yangtse River

Three Gorges
Project12

–Technical Difficulties• Few hydrological monitoring stations– Methodology• Spatially distributed hydrological model• History data analysis : 135-139 m• Field monitoring: 145-156 m• Hydrodynamic modeling–Research Progress• Preparation Stage– Preliminary investigation results• Velocity distribution in Three Gorges
Reservoir
velocity distribution in Three Gorges
Reservoir
2.50-100
100-200
200-300
300-400
400-500
500-550v（m/s）

2.0
1.5
1.0
0.5
0.0
1

2

3

4

5

67

8

9101112month(typical hydrological year=1999, storage level = 156 m)

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– Preliminary investigation results• Tributary flow
flow distribution at Xiangxi River mouth
600500(m3/s)

400
300
200
10000100200300

400

500

600

700800(d/2)(typical hydrological year=1998 , storage level = 156 m)– Preliminary investigation results
Response of Chlorophyll a to tributary flow

Q(m3/s)

Q--chlaLn(chla)14

– Preliminary investigation results• Response of Chlorophyll a to water elevation change
Water elevation

Chlorophyll aThank You !

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