Japan Society of Civil Engineers 100th Anniversary
Commemorative Ceremony – the 3rd RTM on Disaster Management

November 19, 2014

Natural Characteristics of Taiwan
Disasters Caused by Typhoon Morakot

Reconstruction of Alishan Highway

Rational Thoughts2

1. Natural Characteristicsof Taiwan

Natural Disaster Risk
 According to the report by the World Bank (2005) 「NaturalDisaster Hotspots – A Global Risk Analysis」
 In Taiwan, 73.1% of Total Area and Population
Exposed to Multiple Hazard
 Types of Hazard: Cyclones, Floods, Earthquakes,

Landslides

Taiwan4

Typhoon and heavy rain
Map of Typhoon routes, 1985~2005

TaiwanNASA5Typhoon and heavy rain
Geographical features andhydrological background in Taiwan

Average Annual Rainfall (mm/yr)

Average Water Usage per Capita(m3/per capita/yr)

TaiwanPhilippines
Japan
India
Uk
Italy
USA
FranceChina
CanadaAustralia
Saudi Arabia
Average

2.5 times

5.4 times

Slope of River
Dajia River Zhuoshui River

EUR.

Danshui River

Elevation
(m)

Rhine

TaiwanJapan
Shinanogawa

USA
Colorado River

Tonegawa

China
Mekong River

Distance (m)6EurasianPlate

EurasianPlate

Philippine Sea Plate

Distribution of annual earthquakes
500004992849928

1999
Chichi EQ

50000

地震次數
No. of Earthquake
地震次數
5年平均

Avg. of 5yrs
5年平均

地 No.of
震 次 EQ
數40000地 震 次 數

40000

28808
30000

16074

28808

20000

15650
14802

10000
16074

4319
4682

4933

2017

17961

24323

5446
4518

18379
18059
16422

16244

14981
28097
25449

19347

22093
21783

0
16977

18379
18059
16422

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

15650
14802

19347

22093
21783

16977

17961

30000

20000

24323

28097
25449

14981

16244時 Year 間

7Chichi Earthquake, 1999 Sept. 21
ML=7.32505 fatalities, 11,305 injuries

Fault scarp

Shikang dam
8

Chichi Earthquake, 1999 Sept. 21
ML=7.32505 fatalities, 11,305 injuries
Fault scarp

Pifong bridge
9

Characteristic of debris flow in Taiwan(massive volume )Taiwan Ordinary Cases
Fongciou Village

Taiwan Special Cases

Design debris flow

Shibachong River

Sitou

Watershed area

(Lin and Jeng, 2000 )102. Disasters Caused byTyphoon Morakot

Overview of Typhoon Morakot, 2009a ve ry s tro ng deve lopmen t o fconvective cloud in August 3~11, 2009
more than 3,000mm of accumulated
rainfall, breaking the record in Taiwan

Japan

China

Taiwan2009 Aug.7

CWB 08/08/09:00-11:00
QPESUMS 雷達整合回波圖

Philippines
12Affected area of Typhoon Morakot
China

China
Shanghai

Zhejiang
Shanghai

Typhoon’s Path
Time：2009/08/03~11

FujianTaiwanPhilippines
Zhejiang

FujianTaiwanPhilippines
13

Analysis of rainfall characteristics derived from Typhoon Morakot
12~72 hour of continuous rainfall, close to the world record

Accumulated Rainfall (mm)12 hr.

The rainfall envelopeof the world

Rainfall=421.6 x duration^0.475

Typhoon Morakot

72 hr.

Largest Rainfall Envelope of the World
Largest Rainfall Record of the World
Largest Rainfall Record of Taiwan
0807 Flood, 1959
Shirley Typhoon, 1968
Gloria Typhoon, 1963
Herb Typhoon, 1996
Toraji Typhoon, 2001
Nari Typhoon, 2001
Estimated Rainfall of Tsaoling Landslide Lake
Estimated Rainfall of Tongtou
Kalmaegi Typhoon, 2008, Kaoping River
Morakot Typhoon, 2009,

Duration (hr.)
14Kaoping River, high-intensity rainfall with long duration of time

Rainfall Intensity (mm/hr.)

Ming-sheng observation station, Kaoping River

Typhoon Morakot

Morakot 2009/08/08
Sinlaku 2008/09/11
Kalmaegi 2008/07/16
Haitang 2005/07/16
Aere
2004/08/23
Toraji2001/07/28

Duration (HR)15

High intensity rainfall of Typhoon Morakot
more than 2,000mm of accumulated rainfall in 9% area of Taiwan,
mostly in the south
4-day accumulated rainfall as high as 78% of annual rainfall
The highest record

53162

778%

78%

76%

74%

73%

71%

68%

1234

567

Tapu

LiuguiAlishanJashenTouyuan

41Location

Sun-di-men Tzuchih

8/7~10 accumulated

annual rainfall
16

Disasters of Mountainous
Roads in Southern Taiwan

Landslides

Moulin Township

茂林鄉

18

Landslides

Ali Tribe, Wutai Township

霧台鄉阿禮部落19

Debris Flow
Sinfa Village

Liugui District

六龜Sinkai Village

20Damaged roads in southern Taiwan
Road Damage TypeCountyHighway No. 18
ChiayiHighway No. 20

TainanHighway No. 21

Kaoshiung

Highway No. 20,
Route No. 133
Highway No. 3,
Highway No. 28

Taitong

BridgeSlope

No. of Events

Kaohsiung

56

2682

Chiayi

1148

59

Pingtung

141428

Nantou1115

26

Tainan6814

Taitung

5712Taichung257

Yunlin156

Miaoli

235Changhua

303Yilan112

Hualien022

Taoyuan

01

1

Total

112

135247Highway No. 27,
Highway No. 27-1
Pintong

Highway No. 24

Highway No. 17
21

3. Reconstruction of Alishan
Highway１ Hwy18 – 41 locations
2 159甲 – 3
3 162甲 – 21
4 169
– 42
5 149甲 – 17

Bridge broken

162甲149甲Roadbase loss
台18159甲169

Big landslide

Total
123

Damaged spots in the scenic Alishan area

St. 37k

Highway No. 18

N40k

40.5k

18
To Alishan

1838.5k

37.5k38k

To Chiayi

24

St. 59k

Highway No. 18

To Alishan

To Chiyi
25St. 71k

Highway No. 18

NTo Alishan
71.5k
1871k
Rockshed

70.5k

18To Chiayi
26

Reconstruction of Highway No. 18
St. 37k

BeforeAfter

St. 59k

BeforeAfter
27

Reconstruction of Highway No. 18
St. 71k

Before

After

After

After
28

St. 71k

200m

Rock shed

Anchored RW
New bridge of Highway No.18

Reconstruction in Alishan
29

4. Rational Thoughts Roads/bridges are vulnerable to heavy rains Using aerial photo & site investigation to evaluate thehydrology, landslide potential and the safe zone for road N

Remote village

2021

避開敏感集水區旗山溪穩定廊帶荖濃溪河道變遷判釋

Evaluation of Highway Nos. 20 & 21 on the hydrological geology
31Hydrology

To Taitung

NChinshuei river

Lakas riverFuhsing

Butangbunas river

Butangbunastong river
20

Meishiou river
Laonoan river

Yushuei river

Dongzuang river

ChinhoTo Kaohsiung

94年

2009
ChinhoChinhoLaonoanriver

Laonoanriver

H=30m

2012

101年

H=10m

Riverbed of Laonoan river elevated continuously

Chinho-Fuhsing section of Highway No. 20
Riverbed filled with high volume of debris (H > 30m)
After heavy rain in 2012 June 10, add 15~20m to H
May still elevates 30m higher than the present

Meishiouriver

Butangbunas
river

Chinshueriver

34

Unstable ground formation and river

Meishiouriver

Butangbunas
river

Chinshueriver

Meishiou

Elevation(m)Chinshue

750

Butangbunas

700
150-290 1190-1300
300-450
1350-1480 1350-1490
970-1060
1000-1170 1300-1350
1420-1530
740-900
280-460
1520-1690<200 330-500
1340-1510<2001720-1860 1620-1810<200 1390-1530
530-650
1350-1410
2010-2300

650
600
550

96k

97k

98k

99k

100k

101k Mileage

Riverbed variations
There were 3 occasions in the previous 2000 years, the riverbed
was higher than the presentFuhsing
Chinshue river

Height(m)10050

Meishiou

Carbon 14
test results

Morakot80m

200Chinho

0now

12

Thousand years before present

Environmental geology

Flood analysis

Landslide, debris flow and river

Q100 flow fluctuation

Relatively
stablecorridor?

Interim road recovery (~10 yr.)

Embankment, 0.86km

Embankment 2.0km

Elevated, 1.2km

Planed road
Existing road

To Chinhoto Fuhsing

98k+500
99k+400

101k+440

97k+300
96k+440

The recovery plan for Highway No. 20
EL.660m
A2

P1

98k+500

A1

修坡處

A2P17P15Riverbed
EL.620~640m

P13P11P9P7EL.640m

P5P3P1
A197k+300

3D simulation for the bridge section

In summary
The topography, geology and meteorology situations in Taiwan
are vulnerable to typhoon, landslide and earthquake.
Holistic considerations for mountain, river, bridge, road and landdevelopment are important to manage risk from natural disasters.
Challenges from global climate change and extreme weather
conditions：Use practical design and assessment criteria for infrastructuresin mountainous area
Establish rational ways for the prevention, mitigation andrecovery works against natural disasters
Use adaptive measures to meet the need of a changing world
In addition to engineering techniques, there are always valuableviewpoints from social, economical and environmental aspects
that we need to deal with.
41

Thanks foryour attention!

42