landslides and large dams

19
Landslides and large dams David Petley Wilson Professor Hazard and Risk Dean of Research and Global Engagement Durham University, United Kingdom http://blogs.agu.org/landslideblog/ Google: “landslide blog AGU”

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My presentation at the Vajont 2013 conference in Padua. The presentation examines losses associated with large dams in the last few years, and shows in particular that there have been over 500 deaths in landslide-related accidents during dam projects

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Page 1: Landslides and large dams

Landslides and large dams

David PetleyWilson Professor Hazard and Risk

Dean of Research and Global Engagement

Durham University, United Kingdom

http://blogs.agu.org/landslideblog/Google: “landslide blog AGU”

Page 2: Landslides and large dams

VajontThe key lesson in dams

and landslides

Images from Wikipedia

Page 3: Landslides and large dams

Large landslides and dam projects

• But, some landslides have continued to occur on the flanks of reservoirs

• Some, but perhaps surprisingly few, have been fatal

• E.g. Qianjinangping landslide, July 2003, 24 fatalities:

Page 4: Landslides and large dams

Clyde Dam, New Zealand:Successful landslide

management€580 million (2005 value)

Page 5: Landslides and large dams

Existing large damsUN large dam database (2012)

Each red dot is a large dam on the UN database. Existing dams are concentrated in mountain areas, but not in very high mountains

Page 6: Landslides and large dams

Contour map of the density of existing large dams

Existing dams are concentrated in medium but not in very high mountain areas

Few dams here

Large dam densityUN large dam database (2012)

Page 7: Landslides and large dams

Distribution of fatality-inducing landslides 2004-2011

Each dot is a landslide that killed one or more people. Note the focus of landslides in high mountain areas, especially the Himalayas

Page 8: Landslides and large dams

Large dams and fatality-inducing landslide events (2004-2011)

The distribution of fatal landslides and large existing dams does not overlap significantly, especially in the Himalayas

Conclusion: we have mostly built large dams where landslides do not kill many people (NB China)

Page 9: Landslides and large dams

Large dams completed since 1990

Each dot is a large dam constructed since 1990Note:

• Increased numbers of dams in China• Dams starting to be constructed in high mountain areas

There is more dam building now in areas with many landslides

Page 10: Landslides and large dams

Analysis of landslides associated with large dams

• Fatality-inducing landslides between 2003 and 2012 that have been associated with large dams:

500 deaths in 37 landslide events

Page 11: Landslides and large dams

Date Country Location Deaths Indicative dam project NB low certainty

Description

13/07/2003 China Qiangjingping 24 Three Gorges Dam Landslide on banks of reservoir 03/08/2004 India Tehri Dam, Uttranchal 29 Tehri Dam Buried in a tunnel 23/04/2004 China Majuangou, Shaanxi 4 Small scale hydro Landslide at dam construction site 26/04/2005 India Mulliyar, Kerala 10 Small scale hydro Landslide at dam construction site 28/06/2005 India Shahpur, Ghatgar 15 Ghatghar HEP Buried in a tunnel 07/10/2006 China Fangxian C’ty, Hubei 6 Not known Rockfall onto workers en route 15/12/2007 Vietnam Tuong Duong, Nghe An 18 Ban Ve HEP Rockfall onto quarry workers 19/07/2007 China Sujiahekou , Yunnan 29 Sujiahekou HEP Landslide into workers camp 20/07/2007 China Guide County, Qinghai 8 Laxiwa HP Station Landslide at dam construction site 10/08/2007 China Ya'an City, Sichuan 12 Long Tou Shi Dam Landslide at dam construction site 14/08/2007 India Dharla, Himachal Pradesh 62 Ghanvi HEP Landslide into workers village 07/09/2007 Bhutan Chukha dzong 2 Chuka HEP Landslide into workers camp 15/12/2007 Vietnam Tuong Duong, Nghe An 18 Ban Ve HEP Rockfall onto quarry workers 12/05/2008 China Jinhe HEP 22 Jinhe HEP Landslide at dam construction site 20/05/2008 Chile San Fernando 1 Not known Rockfall onto workers en route 07/06/2008 Bhutan Wangkha 12 Tala HP project Rockfall onto workers en route 31/07/2008 China Ya'an City, Sichuan 5 Long Tou Shi Dam Landslide onto workers en route 11/09/2008 Nepal Khare VDC, Dolakha 1 Upper Tamakoshi HP Rockfall onto road construction workers 07/05/2009 Tajikistan Rogun 2 Rogun HEP Landslide at dam construction site 03/06/2009 Vietnam Nam Khoa, Lao Cai 4 Nam Khoa HEP Landslide into workers camp 23/07/2009 China Kangding C’ty, Sichuan 54 Changheba HEP Landslide into workers camp 31/07/2009 China Jinyang C’ty, Sichuan 9 Not known Landslide into workers camp 23/01/2010 Vietnam Ve village, Yen Bai 1 Nam Toc HEP Spoil tip landslide 14/02/2010 India Kinnaur, Himanchal Pradesh 8 Karcham-Wangtoo HEP Landslide into workers camp 15/06/2010 China Kangding county, Sichuan 23 Kangding Longtou HEP Landslide into workers camp 26/07/2010 China Gongshan Drung-Nu, Yunnan 11 Unknown Landslide into workers camp 31/07/2010 Pakistan Patan, Khyber Pakhtunkhwa 3 Patan Hydropower project Landslide at dam construction site 02/08/2010 Nepal Gaurishankar, Dolakha 11 Sipirang River HEP Landslide at dam construction site 15/06/2011 China Shiyan, Hubei 3 Hubei Shyan Longbeiwan Landslide at dam construction site 18/09/2011 India Salim Payel, Mangan 10 Teesta HEP Landslide at dam construction site 18/09/2011 India Teesta HEP, Sikkim 1 Teesta HEP Landslide into workers camp 18/09/2011 India Teesta HEP, Sikkim 7 Teesta HEP Landslide at dam construction site 28/02/2011 India Asiganga, Uttarakashi. 4 Asiganga Phase I Landslide at dam construction site 28/06/2012 China Ningnan C’ty, Sichuan 40 Baihetan HEP Landslide at dam construction site 13/07/2012 China Shuicheng C’ty, Guizhou 3 Maojiahe HEP Landslide into workers camp 30/08/2012 China Liangshan Yi Sichuan 24 Baihetan HEP Landslide at dam construction site 15/05/2012 Turkey Kızıltaş, Dereli, Giresun 4 The Kanat Regulator Landslide at dam construction site

Page 12: Landslides and large dams

Temporal trends in landslide deaths associated with major dam projects

2003 2004 2005 2006 2007 2008 2009 2010 2011 20120

100

200

300

400

500

600

0

25

50

75

100

125

150

Year

Cu

mu

lati

ve

nu

mb

er

of

de

ath

s

An

nu

al

nu

mb

er

of

de

ath

s

Cumulative number of deaths

Annual number of deaths

Page 13: Landslides and large dams

Landslide setting – numbers of landslides

17

11

5

11

2

Construction

Landslide into workers camp or village

Rockfall or landslide at road sites

Spoil tip landslide

Landslide on banks of reservoir

Quarry landslide

Vajont type event

Page 14: Landslides and large dams

Distribution of landslides associated with large dams

Each dot is a landslide associated with a large dam in the period 2003-2012

Note:• Almost all are in Asia• Hotspots are in the Himalayas and in China

Page 15: Landslides and large dams

Landslides associated with major dam projects

Number of landslides

Number of deaths

China

India

Vietna

m

Bhuta

n

Nepal

Turke

y

Pakist

an

Tajikis

tan

Chile

0

2

4

6

8

10

12

14

16

18

0

25

50

75

100

125

150

175

200

225

250

275

Nu

mb

er

of

lan

ds

lid

es

Nu

mb

er

of

de

ath

s

Number of landslides

Number of deaths

Page 16: Landslides and large dams

Time of year of dam-related landslides

Janu

ary

Febru

ary

Mar

chApr

ilM

ayJu

ne July

Augus

t

Septe

mbe

r

Octob

er

Novem

ber

Decem

ber

0

1

2

3

4

5

6

7

8

9

10

Month

Nu

mb

er

of

reco

rde

d la

nd

slid

es

Peak in northern hemisphere summer implies a predominant rainfall trigger

010203040506070

21 19 17 1825

36

5851

3935

2517

Page 17: Landslides and large dams

In summary

• Until now, large dams have mostly been constructed in upland areas with low to medium sized mountains

• Fatal landslide incidence in these areas is generally low• Increasingly we are building dams in very high mountain

areas• Fatal landslide incidence in these areas is high

• In recent years there have been many landslides associated with these projects during their construction, especially in China and India

• 500 people have died in these landslides

Page 18: Landslides and large dams

Proposed dams and dam related landslides in the Himalayan region

Dam: planned or under construction

Fatal landslide associated with a dam

Page 19: Landslides and large dams

Conclusions