1. COUNTERMEASURES AGAINST STORM SURGE May 24th, 2006 Susumu Murata Coastal Development Institute of Technology, Japan

2. Major Typhoon Disasters in Japan No. 18 （1991） No. 18 （2004） No. 13 （1953） No. 26 （1966） Ruth （1951） No. 23 （2004） Kano-gawa （1958） Muroto （1934） Jane （1950） Kitty （1949） Ise-wan （1959） No. 16 （2004） 2nd Muroto （1961）

3. Damage by Typhoon Ise-wan (Sep. 26th, 1959) Timbers and logs washed away to apartment houses 【Damage】●The Number of Victims Dead or Missing５，０９８ ○The Number of Buildings Destroyed Completely or Half　　　１５１,９７３ Levee breaches and inundation disasters

4. Storm Surge High Risk Areas in 3 Major Bay Regions Tokyo Bay （Yokohama～Chiba） Ise Bay （Kawagoe～Tokai） Osaka Bay （Ashiya～Osaka） ■：Below T.P.±0m ■：Below High Water Level ■：Below High High Water Level

5. How to Determine Height of Seawall against Storm Surge Allowance Projected Seawall Height Wave Storm Surge Wave Wash Projected Storm Surge Height Deviation from HWL by Storm Surge High Water Level (HWL) Seabed Projected Seawall Height ＝ HWL＋Storm Surge Deviation＋Wave Wash＋Allowance Conditions of Seawall Design

6. Problem with Storm Surge in Areas Lying below Sea Level ◎65% of seawalls in Japan have sufficient height. ◎93% of seawalls in 3 major bay areas have sufficient height. 【Sufficiency of Seawall Height】 Sufficient 3％ 8km 65％ 9000km 9％ 1176km 4％ 13km 93％ 285km 5％ 657km Temporarily Sufficient Insufficient 22％ 2959km All Japan 3 Major Bay Areas Unknown ◎Once seawalls are breached by a disaster beyond projection, serious damage will occur in these areas. 【Many facilities were constructed more than 40 years ago in 3 major bay areas.】 ◎Aging of facilities protecting areas lying at sea level is progressing. 327km ◎Steady Development of Facility & Enhancement of Credibility of Facility ◎Promotion of Damage Minimization Measures Preparing for Serious Flooding Situation 全327km

7. Future Storm Surge Control Measures in Areas below Sea Level 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 ・Needof 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

8. 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

9. Nemuro（Ｍ7.9） 40％ 【 Probability of great earthquakes occurring in 30 years】 Urgency 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％ Tokachi（Ｍ8.1） 0.5％ Hokkaido North West（Ｍ7.8）0.1％ Sanriku North (Ｍ8.0)7％ (Ｍ7.1～7.6)90％ Akita（Ｍ7.5） 3％ Miyagi（Ｍ7.5）99％ Sanriku South(Ｍ7.7) 70～80％ Yonagunijima（Ｍ7.8）30％ SadogashimaNorth（Ｍ7.8）6％ Sanriku～Boso・Tsunami（Ｍ8.2)20％・Rift（Ｍ8.2）7％ Akinada～Bungosuido（Ｍ6.7～7.4） 40％ Genroku Kanto（Ｍ8.1）0％ Hyuganada（Ｍ7.6） 10％ Minami Kanto（Ｍ6.7～7.2）70％ Tonankai（Ｍ8.1） 60％ Tokai（Ｍ8.0） 86％ Nankai（Ｍ8.4） 50％ Taisho Kanto（Ｍ7.9）0.9％

10. Approach to Storm Surge & Tsunami Disaster Urgent Steady Facilitation of Evacuation Enhancement of Reliability of Coastal Protection Facility Development of Coastal Protection Facility ◎ Promotion of Hazard Map Preparation ◎ Systemization of Storm Surge & Tsunami Information Collection & 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 Non-Facility Approach Facility Development Protect Life Protect Property

11. Urgent plan for risk management on tsunami and storm surge disaster ① Automation and remote control of gates ② Disaster prevention center ③ Functional upgrade of Seawalls ④ Hazard map ⑤ Information transmission facilities ⑥ Evacuation routes Tsunami ! Storm Surge! ⑤Information transmission facilities ① Automation and remote control of gates ⑥Evacuation routes ③Functional upgrade of seawalls ④ Hazard map ②Disaster prevention center