Overview of levees on Yangtze River, China€¦ · Yangtze river, impound flood water of 22.7...

Overview of levees on Yangtze River, China

WU AIQING, WU QINGHUA

Changjiang River Scientific Research Institute，China

Outline

1. Introduction of Levees in China

2.Levee Risks on Yangtze River

3.Reinforcement of levees after 1998 flood

4.Knowledge Gaps and Research Needs

5.Remarks

River system in China

River system in China

Valley Area

River Name

≥50 km2

(rivers)

≥100 km2

(rivers)

≥1000 km2

(rivers)

>10000 km2

(rivers)

Heilong River 5110 2428 224 36

Liao River 1457 791 87 13

Hai River 2214 892 59 8

Yellow River 4157 2061 199 17

Huai River 2483 1266 86 7

Yangtze River 10741 5276 464 45

Rivers in Zhejiang

and Fujian

province

1301 694 53 7

Pearl River 3345 1685 169 12

Out flow River 5150 2467 267 30

Internal flow River 9245 5349 613 53

Total 45203 22909 2221 228

Number of

rivers with basin

area larger than

50km2:45203.

Mountain

rivers: 4053.

Rivers in

flatlands: 4700.

Basin Time Major flood factor Main risks Disaster influence

Yangtze River

1931 Long-term rainfall caused

national flood levee breach in Wuhan

danshuichi Hankou downtown was flooded

1954

The middle and lower reaches flood meeted with

Chuan river, the whole basin flood

Jingjiang flood diversion area. More than 20

breaches from wuxue to tongling reaches

Affected 123 counties and cities, 3.17 million km2 of farmland and

18.8 million people, 33,000 deaths

1998

Whole basin flood, eight peak floods from Poyang lake, Dongting lake and

upper reaches

73,825 risks, including 1,702 major risks and 872 piping breaches, Jiujiang city bursted

23 local dikes collapsed, affecting 2.75 million people, 130,000 km2 of farmland, 345 deaths , ￥50 billion

direct losses

2016

regional floods in the middle and lower reaches .

High water stage and long-term in main stream

50 general risk, among them piping 30 in main

stream

The overwarning water stage of dike section is 11,000 km, among which2950km is the main stream

Yellow River

1933

Heavy rain in the middle reaches caused heavy floods between hekou

town and shangxi county

62 breaches in the middle and lower reaches

30 counties was inundated, 12, 700 people and livestock deaths

Songhua River

1998 main stream flood of Nen

river- Songhua river. 4 bursts in tributaries

and 7 overtopping risks

Affected 52 counties, 8.5 million people and 4 million hm2 of

farmland

Representative flood

Yangtze River Basin (1954)

Yellow River Basin (1933)

Songhua River Basin (1988)

Flood losses from 1950 to 2016

Years

Flood losses from 1950 to 2016

Levees in China

The total length of levees：410,000km

The length of over five rank of dikes ： 270,000km

Standard of

flood

control(year)

≥100 100-50 50-30 30-20 20-10

Rank of dikes 1 2 3 4 5

Distribution of dikes Jingjiang levee in Changjiang River

http://www.lib.whu.edu.cn/~calis/yrrd/txk/slsd.htm

Safety Influence for levee performance

Inhomogeneous levee body

Complicated structures of levee foundation

Characteristic evolution of levee structures

Seepage and river erosion effect

Influence of human-animal-plant activities

Spatial difference

Bank Collapse risk in Jiangsu province(2017)

Cross section of levee

National Key R&D Program for Levees

National Key R&D Program of China:

Evolutionary mechanism of levee risk, rapid hidden denger detection and equipment for levee risk rescue.

Program No.:

2017YFC1502600

Period:2018-2020

Total fund:

19.12 million RMB

Outline





5.Remarks

Yangtze River Basin

Yangtze Rive Basin

Area：1.8 million km2

Main stream： 6397km，No.1 in

China，No.3 in the world

Altitude difference：over 5000m

Rainfall： Spatio-temporal uneven,

70%-90% from May to October

Flood distribution：mainly

appeared in the middle and lower

reaches

Tibetan Plateau Jingjiang dike

Levees on Yangtze River(middle-lower reaches)

Main stream length of middle and lower reaches: 1893m.

Total length of levees(including tributotaries):34,000km.

Main stream levees: 3904km in length,consisting of 35 segments.

Jingjiang dike—— a protective barrier

Yichang city Wuhan city

Jingjiang dike

182.35km

Long live pagoda

(1548)

Typical cross section of levees

Two layers of

ground structure:

Clay(soil) layer at

the surface.

Fine sand beneath

the soil layer.

Design standard：

from 3-5 years in

1950 to 20-100

years at present. Fine sand layer

Clay layer

Bapu levee, Hubei

Fine sand layer

Clay layer

Huanggang levee,Hubei

Typical levee risks on Yangtze Rive

Piping risk

Bank collapse risk

Contact scour risk

Overtopping break risk

Seep water risk

Slope sliding risk

Cracking risk

Piping risk in Honghu,2016

Leakage hold risk in Yangxin,2016 Seep water risk in Honghu, in 1998

Overtopping break risk in Wuhan, 2016

Flood event of Yangtze River basin in 1954

Flood feature:

• Hundred year flood，whole basin.

• Catastrophic flood.

• Exceeded warning water level in the whole middle and lower reaches.

Levee risks:

• 61 natural breaches and 13 man made breaches in the main dike.

• Countless breaches of branch and local levees.

• More than 5000 risks happened in the Jingjiang levee, in which there were 2400 large risks, with 1791 piping.

Levee of Wu han City in 1954

Flood losses：

• Influence rage: 123 cities and counties

• Submerged 47.55 million acres.

• Affected population: 18.88 million.

• Fatalities: 33,000 persons.

• Direct economic loss: more than 10 billion RMB. Breaching of Wuhan City Levee in 1954



Flood diversions and breaches in the middle reach of Yangtze River, 1954


Flood feature:

Hundred year flood，whole basin.

Catastrophic flood，the peak flow of 82,000m3/s.

359 km middle and lower reaches above historical high water level.

Levee risks:

One large breach in the Jiujiang levee , Wuhan City flooded, and 1975 breaches in the influent dikes.

73,825 risks happened in the middle and lower of Yangtze Rive, in which there were 1702 large risks（872 piping risks,51.2%).

Levee of Wuhan City in 1998


Flood losses：

Influence rage: more than 12 provinces.

Submerged land: 3.58 million acres.

Affected population: 100 million.

Fatalities : 1800 persons.

Direct economic loss: more than 150 billion RMB.

Breaching of Jiujiang City Levee in 1998

Plugging with big ship


Province Piping

risk

Bank

collapse

risk

Seep

water

risk

Slope

sliding

risk

Leakage

hold risk

Culvert

risk

Sinking

pit risk

Other

risk

Total

Hubei 320 14 35 34 111 19 2 17 552

Hunan 393 23 3 155 36 21 11 81 723

Jiangxi 92 6 1 63 68 28 3 8 269

Anhui 61 7 1 18 16 6 0 6 115

Jiangsu 6 31 4 0 1 0 1 0 43

Total 872 81 44 270 232 74 17 112 1702

percenta

ge 51.2% 4.8% 2.6% 15.9% 13.6% 4.3% 1.0% 6.6% 100%

Piping risks with highest percentage.

Large risks in the middle and lower reaches in 1998

Flood benefits of the Three Gorge project (completion of the Three Gorge project in 2006)

Reservoir of the Three Gorges:

• Total storage：39.3 billion m3.

• Maximum Storage level：175m.

• Construction: 1994 to 2006.

• Flood control：flood control storage 22.2 billion m3.

• Generate electricity：installed capacity 22400 MW.

• Shipping：50 million ton per year. Three Gorges Project


Flood feature:

Worst regional flood since1998.

Exceeded warning water level in the 295 km from Jianli to Shanghai.

Levee risks:

Only few breaches in the local dikes.

50 general risks happened, with 30 piping risks(51.2%),in the middle and lower of breaches.

Piping risk in Wuhan（2016）

Benefits of the Three Gorge project in 2016

Combined dispatching: 30 reservoirs of upper reaches of Yangtze river, impound flood water of 22.7 billion m3

Reduced the water level of 0.2-1.3m, from Jingjiang to Wuhan.

Reduced Chenglingji’s highest flood level by 1m.

Reduces the warning level stage of levees by 250 km.

Protected 25,000 land, and 380 thousand of population.

The Three Gorges reservoir group has played a significant role in flood control in the Yangtze river basin.

The Three Gorges reservoir group has played a significant role in flood

control in the Yangtze River basin

2.4 Flood benefits of the Three Gorges project

Satellite map of Yangtze River

Highest safety stage

Warning stage

66800 63600

34600

44.67 45.22

41.37

The Three

Gorges

Outline





5.Remarks

Strengthen Dikes- after the flood in 1998

Construction work to strengthen dikes from 1999 to 2002, with the total investment of 29.1 billion RMB, which was the 10 times of previous 50 years.

Recovery water area by 2900km2.

Increased storage by 13 billion m3

The flood control standard increased to 100 years from 20years, in most of main dikes.

Seepage control construction

Reinforced flood-diversion sluice of Jinjiang

Strengthen Dikes- after the flood in 1998

Cutoff wall construction Bank protection works Inspection of cutoff wall

Seepage control works: cutoof wall, and weighted cover

combined with relief well.

Bank protection works:underwater toe protection works, and

slope protection works.

Investment for reinforcement of hidden risks

Hubei prov. Hunan prov. Jiangxi prov. Anhui prov.

108 RMB

Quality check after 20 years (2018)

Outline





5.Remarks

Equipped rescue technology

Flood fighting mainly by traditional methods with large number of persons. Research gaps: prefabricated and portable equipments for flood fighting ?

Knowledge Gaps

Action scheme of levee researches

A National Key R&D Program of China has been

approved:

Name:Evolutionary mechanism of levee risk, rapid hidden

trouble detection technology, and equipment of levee risk

rescue（No.2017YFC1502600.

Research period:2018-2020.

Total fund: 19.12 million dollars.

Research staffs:10 participant organizations.


2 Universities

Hohai University

Zhengzhou University

2 Research institutes

Changjiang River Scientific Research institute

China Institute of Water Resources and Hydropower Research

4 Public welfare institutions

China Renewable Energy Engineering Institute

Bureau of Hydrology, CWRC

Bureau of Henan Yellow River, YRCC Water conservancy and hydropower

Water conservancy and hydropower survey

2 State-owned enterprises

Changjiang Institute of Survey, Planning, Design and Research

Sinohydro foundation engineering co., LTD

Research

Apply

Study

Production


Part1：Dike engineering classification and informatization management

Classification criterion of dike engineering based on security

Research informatization management of dike engineering applied 3D-GIS

Establishing of full life circle database for dike engineering Informatization management


Part2：Mechanism of levee risks

Research mechanism of levee risks, e.g., piping risk and bank collapse risk.

Analyze which kind of levee risks would be threatening to the levees, and describe the conditions.

Physical model of piping risk


Part3 ： Risk assessment and management of dike engineering

Research risk analysis method of levee safe operation, based on flood-rainfall-levee conditions.

Research control standards and risk management for operation safely of dike engineering. Risk analysis of levee


Part4：Risk identification , monitoring and early warning system

Research monitoring and early warning system, considering levee safely, based on flood-rainfall-levee conditions.

Development of information security management system for flood analysis and rescue.


Part5：Techniques and equipments for rapid detection of hidden trouble by geophysical methods

Development techniques and equipments for rapid detection of hidden trouble.

Making efford to overcome difficulties relavant with detection of hidden trouble of levees by geophyics methods. Detecting hidden trouble


Part6：Techniques and equipments of levee risk rescue

Development new-style, portable and prefabricated techniques and equipments, improving rescue efficiency.

Relief wells

Outline



3.Rescue Measures of Levee Risks


5.Remarks

Flood is one of major disasters, which threatens humans.

Great efforts have been made by Chinese government to defense the flood threats, and a great achievements have been fufilled, esp. for flood control in Yangtze River basin

The levee risks are complicated. We are still facing challenges in aspects of knowledge about mechanism of levee risk, rapid detections,efficient equipment developments for rescue,etc.

We hope to have a good cooperation and philosophy exchanges in our LC team in the future.

Thanks for your attention！

Overview of levees on Yangtze River, China€¦ · Yangtze river, impound flood water of 22.7...

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Transcript of Overview of levees on Yangtze River, China€¦ · Yangtze river, impound flood water of 22.7...