COUNTERMEASURES AGAINST STORM SURGE

May 24th, 2006

　 Susumu Murata

Coastal Development Institute of Technology, Japan

Major Typhoon Disasters in JapanMajor Typhoon Disasters in Japan

Kitty（ 1949 ）Ise-wan

（ 1959 ）

Ruth（ 1951 ）

Jane（ 1950 ）

2nd Muroto（ 1961 ）

Muroto（ 1934 ）

Kano-gawa（ 1958 ）

No. 13（ 1953 ）

No. 26（ 1966 ）

No. 18（ 1991 ）No. 18

（ 2004 ）

No. 23（ 2004 ）

No. 16（ 2004 ）

Damage by Typhoon Ise-wan (Sep. 26th, 1959)Damage by Typhoon Ise-wan (Sep. 26th, 1959)

【 Damage 】● The Number of Victims

Dead or Missing 　５，０９８○The Number of Buildings Destroyed 　　 　　　　　　　　 Completely or Half 　　　１５１ ,９７３　　　　　　　　　

Levee breaches and inundation disasters

Timbers and logs washed away to apartment houses

Tokyo Bay （ Yokohama ～Chiba ）

Ise Bay （ Kawagoe ～ Tokai ）

Osaka Bay （ Ashiya ～ Osaka ）

　 Below High Water Level

　 Tokyo Bay

Ise Bay

Osaka Bay

Total

Area （ km2 ） 116 336 124 577

Population (thousand)

1,760 900 1,380 4,040

1:500000

140 ‹E

35 ‹N

36 ‹N

140 ‹E

35 ‹N

36 ‹N

1:500000

137 ‹E

34 ‹N

35 ‹N

137 ‹E

34 ‹N

35 ‹N

1:500000

135 ° E

34° N

35° N

135 ° E

34 °N

35 °N

■ ： Below T.P.±0m■ ： Below High Water Level■ ： Below High High Water Level

Storm Surge High Risk Areas in 3 Major Bay RegionsStorm Surge High Risk Areas in 3 Major Bay Regions

Tokyo Bay （ Tokyo Port ） Ise Bay （ Nagoya Port ） Osaka Bay （ Osaka Port ）

ForceIse-wan Typhoon （ Sep. 195

9 ） Ise-wan Typhoon （ Sep. 1959 ） Ise-wan Typhoon （ Sep. 1959 ）

Projected Storm Surge Height

Ｔ．Ｐ． ＋３．０～４．０　m

Ｔ．Ｐ． ＋４．５ m Ｔ．Ｐ． ＋３．９ m

Storm Surge Deviation

２．０～３．０ m ３．５ m ３．０ m

HWL Ｔ．Ｐ． ＋１．０　 m Ｔ．Ｐ． ＋１．０　 m Ｔ．Ｐ． ＋０．９　 m

Course Worst Scenario Ise-wan Typhoon Muroto Typhoon

Conditions of Seawall Design

High Water Level (HWL)

Wave Wash

AllowanceProjected Seawall Height

Projected Storm Surge Height

Seabed

Deviation from HWL by Storm Surge

How to Determine Height of Seawall against Storm SurgeHow to Determine Height of Seawall against Storm Surge

Projected Seawall Height ＝ HWL ＋ Storm Surge Deviation ＋ Wave Wash ＋ Allowance

Wave Storm Surge

【 Sufficiency of Seawall Height 】

◎Once seawalls are breached by a disaster beyond projection, serious damage will occur in these areas.

◎Steady Development of Facility & Enhancement of Credibility of Facility◎Promotion of Damage Minimization Measures Preparing for Serious Flooding Situation

◎Aging of facilities protecting areas lying at sea level is progressing.

◎65% of seawalls in Japan have sufficient height.◎93% of seawalls in 3 major bay areas have sufficient height.

【 Many facilities were constructed more than 40 years ago in 3 major bay areas. 】

～ 1960

1961 ～ 1965

1966 ～ 1975

1976 ～ 1985

1986 ～

Unknown

Sufficient

Temporarily Sufficient

Insufficient

Unknown

22 ％2959km

5 ％657km

9 ％1176km

All Japan

93 ％285km

4 ％13km

3 ％8km

65 ％9000km

全 327km

50%

12%

15%

10%

10%3%

327km

Problem with Storm Surge in Areas Lying below Sea LevelProblem with Storm Surge in Areas Lying below Sea Level

3 Major Bay Areas

Recommendation by Panel on Storm Surge Control Measures in Areas below Sea Level (January 2006)

Ⅰ Basic aspects of storm surge control measures in areas below sea level

・ Need 　 of damage minimization against large-scale inundation

・ Future Storm Surge Control Measures in Areas below Sea Level

Ⅱ Specific measures to be taken

1.Measures to fully prevent inundation through the existing storm surge defense plans

ⅰSteadily constructing storm surge defense facilities

ⅱSecuring the reliability of disaster defense facilities

ⅲEnhancing normal management system

2.Damage minimization measures against large-scale inundation

ⅰMinimizing inundated areas

ⅱShifting to a way of living free from inundation damage

ⅲEnsuring quick and safe evacuation and relief

ⅳKeeping facilities operational for rapid relief, restoration and rehabilitation

Future Storm Surge Control Measures in Areas below Sea LevelFuture Storm Surge Control Measures in Areas below Sea Level

3.Accumulation and dissemination of storm surge defense knowledge

4.Additional challenge to be undertaken to ensure the security against storm surge disasters

ⅰInvestigations and studies concerning the evaluation of structural strength of storm surge protection facilities against external forces

ⅱInvestigations and studies concerning the evaluation of probability of storm surge as a design external forces

ⅲInvestigations and studies concerning the refinement of storm surge protection facilities inspection methods for their efficient maintenance, repair technology and deterioration control measures

ⅳInvestigations and studies concerning the development of methods for quickly restoring levees breached by storm surge

ⅴInvestigations and studies concerning protection measures against sea level rise due to global warming and land use in coastal areas

ⅵInvestigations and studies concerning disaster protection systems (including tax and insurance systems) in coastal areas

Urgency of Large-Scale EarthquakeUrgency of Large-Scale Earthquake

c.f.【 Encounter Risk in 30 years 】

Killed (Traffic Accident): ０．２％Injured (Traffic

Accident): ２０％

Killed or Injured (Fire): ０．２％Encountered (Fire): ２％

【 Probability of great earthquakes occurring in 30 years 】

Nemuro （Ｍ 7.9 ）40 ％

Tokachi （Ｍ 8.1 ）0.5 ％

Sanriku North( Ｍ 8.0)7 ％

( Ｍ 7.1 ～ 7.6)90 ％

Miyagi（Ｍ7.5） 99％

Minami Kanto（Ｍ 6.7～7.2） 70％

Taisho Kanto（Ｍ7.9） 0.9％

Genroku Kanto（Ｍ 8.1 ） 0 ％

Tokai（Ｍ 8.0）86％

Tonankai（Ｍ 8.1 ）60 ％

Nankai （Ｍ 8.4 ）50 ％

SadogashimaNorth （Ｍ 7.8 ）

6 ％

Akita（Ｍ 7.5）3％

Hokkaido North West（Ｍ 7.8）0.1％

Hyuganada （Ｍ 7.6 ）10 ％

Sanriku ～ Boso・ Tsunami （Ｍ 8.2)20 ％・ Rift （Ｍ 8.2 ） 7 ％

Akinada ～ Bungosuido（Ｍ 6.7 ～ 7.4 ）

40 ％

Yonagunijima（Ｍ 7.8 ） 30 ％

Sanriku South( Ｍ 7.7)70 ～ 80 ％

Enhancement of Reliability of Coastal Protection Facility

Development of Coastal Protection

Facility ◎ Promotion of Hazard Map Preparation

◎ Systemization of Storm Surge & Tsunami InformationCollection & Dissemination

◎ Inspection of Seawall & Flood Gate Condition

◎ Management of Facility Condition including Maintenance & Repair based on Inspection Record

◎ Minimization of Damage to Property as well as Life

Protect Life Protect Property

Urgent Steady

Approach to Storm Surge & Tsunami DisasterApproach to Storm Surge & Tsunami Disaster

Facilitation ofEvacuation

Non-Facility Approach Facility Development

① Automation and remote control of gates ② Disaster prevention center ③ Functional upgrade of Seawalls

① Automation and remote control of gates

⑥Evacuation routes

②Disaster prevention center

⑤Information transmission facilities

③Functional upgrade of seawalls

Tsunami !

Storm Surge!

④ Hazard map ⑤ Information transmission facilities ⑥ Evacuation routes

④ Hazard map

Urgent plan for risk management on tsunami and storm surge disasterUrgent plan for risk management on tsunami and storm surge disaster