Adaptation Strategy for Climate Change in Japan

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French – Japanese – Dutch workshop on impacts of climate change on hydrology Adaptation Strategy for Climate Change in Japan

July 15, 2008 Toshio Okazumi Director for International Water Management Coordination Ministry of Land, Infrastructure, Transport and Tourism Government of Japan 1. Present conditions Japan is vulnerable to climate change. in Japan

Kinki Region Kanto Region A

y S a h Ikebukuro s i e n

Station R n Ueno a

i k v

Station S e

Kanzaki River K u Kameido R a m nd i

a v

Amagasaki Ri i Station

ved r e

Station Shin-Osaka Station a r

Tokyo Shinjuku R Kinsicyo

Old Edo River

Station i

Station v Station e r r River Ara Shibuya Osaka Station Neya River Shibu Yodo River Station ya Ri M ver Osaka Castle e Hirano gu ro Tennouji Station River R Toneiv River er

Elevation Elevation

About 50% of population 3m – 4m and about 75% of 3m – 4m 1m – 3m 1m – 3m 0m – 1m property on about 10% of 0m – 1m -1m – 0m -1m – 0m -1m – -1m – Water Area land lower than water Water Area levels in rivers during flooding 1. Present conditions Japan, France and the Netherlands in Japan１．我が国の現状

関東地方

Japan France The Netherlands

・Area：378,000km2 ・Area：547,000km2 ・Area：42,000km2 ・Many short steep rivers. ・Almost nation land is Gently ・Rhine River, Maas River, Schelde Geographical characteristics ・Sediment problems because of rolling plain and hill River as mild slope international poor soil ・South Pyrenees and East Alps are river ・Flood plain area is located by precipitous mountains ・Delta and low area alluvial fan and riverside Name of River Tone River Seine River Rhine River Profile of Basin Area About 17,000km2 About 78,000km2 About 185,000km2 represent ative length of river 322km 776km 1,320km river Average bed slope About 1/175 About 1/1,650 About 1/2,600 largest flow discharge 17,000m3/s(1947) 2,400m3/s (1910) 13,000m3/s (1926) annual mean rainfall 1,718mm About 1,000mm About 800mm Climate 100 year daily precipitation characteristics 376mm（Tokyo） About 79.4mm (Montsouris) 80mm（de Valdo） 100 year hourly precipitation 94mm（Tokyo） About 47.4mm (Montsouris) 40mm（ de Valdo ） 2. Outline of the IPPC Mechanism of global warming and climate change (impacts on water-related disasters) AR4 Report

Large volumes of greenhouse gas emissions cause CO2 concentration in the air to rise and increase heat absorption, resulting in temperature rise. Thus, global warming occurs.

Melting of glaciers, ice caps and Thermal expansion Change in Change in snow ice sheets of sea water evapotranspiration accumulation condition

Sea level rise (Maximum rise: 59 cm) More intense typhoons Increase of More frequent heavy Earlier snow melt precipitation by a rains and droughts and reduction of factor of 1.1 to 1.3* discharge

Change in water use Increase of river flow rate pattern

MoreMore frequentfrequent highhigh tidestides andand coastalcoastal MoreMore frequentfrequent MoreMore seriousserious debrisdebris flowflow HigherHigher riskrisk ofof droughtdrought erosionserosions floodsfloods 2. Outline of the IPPC Rises of temperature and sea level AR4 Report

-Temperature is expected to rise by about 0.2℃ per decade in the next 20 years. -Global average surface temperature is expected to rise by 1.8 to 4.0℃ in 100 years' time from now. -Global average sea level is expected to rise by 18 to 59 cm in 100 years' time from now. -Global warming and sea level rise will continue over several centuries even if green-house gas emissions

are controlled. 700

600 ・Average temperature ・Average sea level 500 水 ) 位

℃ 400 変 Case where CO2 concentration in 2000 300 will remain unchanged 化 Peak 20th century Rise of 4.0℃ 200 590mm

( 100 m m 0 Rise of 1.8℃ ) -100 Change in sea level (mm) level in sea Change -200 1860 1880 1900 1920 1940 1960 1980 2000 2020 2040 2060 2080 2100 Source: Data prepared by the River Bureau based on the IPCC AR4 WG1 Report

Rise of global average surface temperature ( surface temperature average Rise of global ・Rises of average temperature and sea level at the end of the 21st century

Year A1: High growth oriented society Society achieving both Society achieving high A1Fl: Dependent on fossil energy sources global environmental economic growth A1T: Dependent on non-fossil energy sources protection and dependent on fossil A1B: Emphasis on the balance among various economic development energy sources energy sources A2: Multipolarized society About 1.8℃ About 4.0℃ B1: Sustainable growth oriented society Temperature rise (from 1.1℃ to 2.9℃) (from 2.4℃ to 6.4℃) B2: Emphasis on regional initiatives Source: Sea level rise Sea level rise ２６～５９ｃｍ IPCC AR4 WG1 (Working Group 1) Summary for Policymakers (Japan Meteorological Agency) -Solid lines indicate rises of global average surface temperature in each scenario identified using multiple models. -Shaded areas indicate the range of standard deviations of average annual temperature for each model. Source: IPCC AR4 WG1 Report 3. Impacts of Resolution of climate change prediction models heavy rains

Resolution気候変動の予測を行うモデル of climate change prediction models has been improved year by year. の解像度は年々進歩

IPCCＩＰＣＣ１次報告書（１９９０） First Assessment Report (1990): Horizontal resolution of about 500水平解像度 km 約500km

IPCCＩＰＣＣ２次報告書（１９９６） Second Assessment Report (1996): Horizontal resolution of about 250水平解像度 km 約250km

IPCCＩＰＣＣ３次報告書（２００１） Third Assessment Report (2001): Horizontal resolution of about 180水平解像度 km 約180km

IPCCＩＰＣＣ４次報告書（２００７） Fourth Assessment Report (2007): Horizontal resolution of about 110水平解像度 km 約110km

GCM20GCM20 and RCM20:、RCM20 Horizontal ※メッシュの大きさを表現したもので、実際のメッシュ箇所とは関係ないMesh sizes are simply indicated regardless of actual mesh locations. resolution水平解像度 of about 20 約 km20km Prediction model in this河川局作成 study 3. Impacts of Estimation of increased rainfall in region heavy rains

Future rainfall amounts were projected as a median value in each region of

Average rainfall in 2080-2099 period Average rainfall in 1979-1998 period ② The above equation was obtained based on the maximum daily precipitation in the year ① at each survey point identified in GCM20 (A1B scenario).

① Hokkaido 1.24 ④ ② Tohoku 1.22 ③ ⑧ ③ Kanto 1.11 ⑤ ④ Hokuriku 1.14 ⑨ ⑥ ⑤ Chubu 1.06 ⑦ ⑥ Kinki 1.07 ⑩ Legend ⑦ Southern Kii 1.13 ⑪ 1.20～1.25 ⑧ San-in 1.11 1.15～1.20 ⑨ Setouchi 1.10 1.10～1.15 ⑩ Southern Shikoku 1.11 1.05～1.10 ⑪ Kyushu 1.07 1.00～1.05 3. Impacts of Declining return period by increasing rainfall heavy rains

Return period of flood is declining by increasing rainfall in the future. Therefore declining future flood safety level is estimated.

【Image of declining return period at certain area】 Maximum daily rainfall × 1.2 return period

future current

1/100

current data projected data 1/ 50

Rainfall probability sheets

rainfall r 3. Impacts of Declining the degree of safety level heavy rains

Impact for flood safety level by changing rainfall after 100 years Declining the degree of safety against flood 1/200 （CurrentTarget ） 1/150（CurrentTarget） 1/100（CurrentTarget ）（annual exceedance probability）（ by increasing future rainfall Region Future flood safety level probability annual exceedance Number of Number of Number of river system river system river system 200

Hokkaido －－ 1/40 ～ 1/70 2 1/25 ～ 1/50 8 Flood safety level 175 Tohoku －－ 1/22 ～ 1/55 5 1/27 ～ 1/40 5 150 1/90 ～ 1/120 3 1/60 ～ 1/75 2 1/50 1 Kanto 125 Hokuriku －－ 1/50 ～ 1/90 5 1/40 ～ 1/46 4 100 Cyubu 1/90 ～ 1/145 2 1/80 ～ 1/99 4 1/60 ～ 1/70 3 75 Kinki 1/120 1 －－－－ 50 Southern Kii －－ 1/57 1 1/30 1 25 ） Saninn －－ 1/83 1 1/39 ～ 1/63 5 0 Current Target Hokuriku Shikoku Southern Kyuusyuu Kanto Hokkaido Tohoku Setouchi Cyubu Saninn Kinki 計北東関北中近紀 Southern Kii 山瀬四九 Setouchi 1/100 1 1/82 ～ 1/86 3 1/44 ～ 1/65 3 画海北東陸部畿伊陰戸国州 Southern Shikoku －－ 1/56 1 1/41 ～ 1/51 3

道 ③ ② ① ① 南内南 ③ Kyusyu －－ 1/90～1/100 4 1/60～1/90 14 ② 部 ① 部 All Japan 1/90 ～ 1/145 7 1/22 ～ 1/100 28 1/25 ～ 1/90 47 ① （ nuleceac probability annual exceedance （ nuleceac probability annual exceedance

Flood safety level 150 100 Flood safety level 125 75 100 75 50 50 25 25 ） Kyuusyuu Kanto Shikoku Southern Hokuriku Current Target Hokkaido Tohoku Setouchi Cyubu Kinki 0 計北東関北中近紀山瀬四九 0 計北東関北中近紀 Southern Kii 山瀬Saninn 四九 Hokuriku Shikoku Southern Kyuusyuu Kanto Cyubu Hokkaido Tohoku Saninn Kinki Setouchi Current Target Southern Kii ）画海北東陸部畿伊陰戸国州画海北東陸部畿伊陰戸国州道 ⑤ ② ⑤ ④ 南 ① 内南 ④ 道 ⑤ ① ④ ③ 南 ⑤ 内南 ⑭ ① ③ ② ⑤ ④ ⑤

① ⑧ 部 ③ 部 ② 部 ③ 部 ③ ⑤ ③ ① ④ ⑧ ③ ⑤ ⑭ ② ① ① ① ① ③ ④ ① ※ Circled number is number of calculated river system 石狩川 (北海道） 3. Impacts of Changes of peak runoff by future rainfall heavy rains

北上川 Estimations（東北） of future rainfall are about ×1.0 ～×1.5 compare to current rainfall. Peak runoff will be estimated about ×1.0 ～×1.7 compare to current rainfall in 9 major rivers.

利根川計画降雨量の増加と基本高水のピーク流量の変化 × × （関東） Design Rainfall 1.0 1.1 ×1.2 ×1.3 ×1.5

Ishikari Riv. Design Level Basin Area Peak Runoff of Design Flood (Hokkaido)黒部川１／１５０ 12,697ｋｍ2 18,000 m3／s 20,500 23,000 25,600 30,700 （北陸） Kitakami Riv. １／１５０ｋｍ2 3／ (Tohoku) 7,070 13,600 m s 15,700 17,800 19,900 24,000

Tone雲出川 Riv. About 21,000 m3／s １／２００ 5,114ｋｍ2 23,600 25,900 27,900 31,800 (Kanto)（中部） (Calculated by 1/200)

Kurobe Riv. １／１００ 667ｋｍ2 7,200 m3／s 8,100 8,900 9,700 11,300 (Hokuriku)紀の川（近畿） Izumo Riv. 2 3 (Cyubu) １／１００ 541ｋｍ 8,000 m ／s 9,000 9,900 10,900 12,800

Kinokawa太田川 Riv. １／１５０ｋｍ2 16,000 m3／s (Kinki)（中国） 1,574 17,600 19,700 21,600 25,400

Oota Riv. (Cyugoku) １／２００ 1,505ｋｍ2 12,000 m3／s 13,100 14,700 16,300 19,400 那賀川 Naga（四国） Riv. (Shikoku) １／１００ 765ｋｍ2 11,200 m3／s 12,800 14,500 16,100 19,300

Kase嘉瀬川 Riv. １／１００ 225.5ｋｍ2 3,400 m3／s 3,800 4,100 4,500 5,300 (Kyusyu)（九州） 0% 20% 40% 60% 80% 100% 120% 140% 160% 180% 4. Impacts of More frequent and serious droughts droughts

Comparison between present conditions(1979 to 1998) and future rainfall(2080 to 2099) in Class A river Comparison between present rainfall and predicted rainfall after 100 years shows decrease in most area in March - June

Reduction of river flow in the periods requiring irrigation water, e.g. during the surface soil Legend

puddling in paddy fields, may be Future water volume/present water deteriorated to water use for volume ≧ 1.4 1.2 ≦ Future water volume/present rice farming. water volume < 1.4

1.0 ≦ Future water volume/present water volume < 1.2

0.8 ≦ Future water volume/present water volume < 1.0

Future water volume/present water volume < 0.8

Spring (March through June)

Source: Water Resources in Japan 2007, Land and Water Bureau, Ministry of Land, Infrastructure and Transport 4. Impacts of Frequent and more serious droughts droughts

In the upper Tone River, snow cover With global warming, is likely to decrease considerably. (i) earlier snow melt and (ii) reduction of snowfall That will accompany the reduction of induce changes in river flow rate, and river flow rate in the snow melt (iii) earlier surface soil puddling in paddy fields is season or in early spring. expected to cause the annual water demand pattern to change and to have serious impacts on water use.

ChangeChange inin snowsnow covercover inin 100100 years'years' timetime duedue toto furtherfurther globalglobal warmingwarming (Fujiwara)(Fujiwara) (ii) Reduction of river (i) Earlier discharge due to earlier flow rate due to snow melt 300 reduction of the amount Average平均 of snowfall 250 Future将来

200 Reduction of river flow during the 積 surface soil puddling in paddy fields 雪 150 深 cm） 100 /sec) 3 Snow cover (cm) cover Snow 50 Future将来 Present現況 0 10月1日October 1 November 11月 1日 1 December 12月1日 1 January 1月1日 1 February 2月1日 1 March 3月 1日1 April 4月1日 1 5月1日May 1

*Prepared by Water Resources Department, Water and Land Bureau, Ministry of River flow (m Land, Infrastructure and Transport based on Regional Climatic Model (RCM) 20, a global warming prediction model, developed by Japan Meteorological Agency. (iii) Insufficient river flow even when the surface puddling starts earlier (requiring large amounts of irrigation water)

January April Surface soil July October puddling period Release of reservoir water not contributing to effective water use Where the reservoir is full, released water is not used effectively. Source: Water Resources in Japan 2007, Land and Water Bureau, Ministry of Land, Infrastructure and Transport Impacts of sea level rise: 5. Impacts of Increase of areas below sea level, and of risks of inundation due to high tides sea level rise Increases of below-sea-level areas in three large bay areas (Tokyo Bay, Ise Bay and Osaka Bay)

Ashiya City to Osaka City Kawagoemachi to Tohkai City Yokohoma City to Chiba City

Osaka Bay Ise Bay Tokyo Bay

*Prepared by the River Bureau based on the national land-use digital information. *Shown are the areas at elevations lower than sea level shown in a three-dimensional mesh (1 km x 1 Areas with flood risks due to km). Total area and population are based on three-dimensional data. *No areas of surfaces of rivers or lakes are included. *A premium of 60% is applied to the potential flood risk area and to the population vulnerable to flood risk high tides will increase. in the case with a one-meter rise of sea level.

Rate of Present現状 After海面上昇後 sea level rise increase倍率面積（Area (kmk㎡）2) 577 879 １．５人口（万人）Population (Million) 4044.04 5935.93 １．５ 6. Japan's response Recommendations of this study to climate change

Climate change due to global warming is expected to induce the following phenomena in coastal and low-lying areas. -More frequent heavy rains and more intense typhoons Frequent and serious flood and sediment disasters -Sea level rise and more intense typhoons Frequent and serious high tides and coastal erosions -Wider range of variation of rainfall intensity and change of river flow regime Frequent and serious droughts

Recommendation1. Basic concept for Future ideal society Combining mitigation and adaptation aiming at ‘’Sustainable and Water Disaster Adaptable Society’’

Recommendation2. Basic direction of climate change adaptation measures

1. Adaptation measures to achieve "zero casualty" should be considered because ‘’Zero damage’’ from disasters is difficult. 2. In a nerve center like the Tokyo metropolitan area, intensive efforts should be made such as preventing from ceasing national function 6. Japan's response to Recommendations3. Multiple measures for increasing in hazard climate change

Red figures indicate present degree Blue figures indicate future of safety against flood. Image of flood disaster adaptation measures degree of safety against flood. Present Future （For example, after 100 years）

1/150 1/150

Degree of safety against Degree of safety against Reconfiguration of flood flood presently aimed at river improvement presently presently would deteriorate with for increasing aimed at future increase of Adaptation by future increase of external force precipitation. Structural measures

1/70 Degree of Degree of safety against safety against Degree of safety flood aimed at against flood flood against flood 1/40 currently aimed at in presently 100 years' time Degree of 1/20 secured 1/20 Deterioration of the safety against degree of safety against flood secured flood currently secured

Comprehensive flood control measures Adaptation measures based on regional development through such actions as restrictions on and review of land use Recommendation4. Importance of Flood Risk Assessment 6. Japan's response to climate change ‐ ex) Adaptation measures programming in river basin

Flood Analysis in Tone River

Small River Bank of Road and Railway Flooding area IV Flooding Area V

入間台地 Flooding Area VI Area Flooding Image of 【Flooding Area II】 Flooding AreaIII

Each flooding area divides into blocks by river, bank of road and railway. Measures Flooding Area I will be set up by each blocks.

Flooding Area II

Divide flooding areas based on Its phenomena 6. Japan's response to Recommendation4. Importance of Flood Risk Assessment climate change ‐ Concept of Flood Risk Assessment

[Hazard Index] is increasing by Climate Change. For reduction of [Disaster risk] , increasing [Disaster Prevention Index] and reducing [Affection Index] by adaptation measures such as improvement of facility, revise of land use, enforce of emergency response

Hazard Index × Affection Index Disaster Risk ＝ × Probability Disaster Prevention Index ・Hazard Index : Natural hazard and Land condition （Climate, Hydrology, Land Feature, Geologic Condition, etc and Scale of Hazard）・Affection Index : Social vulnerability of disasters （Inundation people, Inundation houses, impacts of Road, Railway, Lifeline, etc）・Disaster Prevention Index : Disaster prevention activity by Central Government, Local Government, community （Present status of facility improvement, Public preparedness for disasters）

犠

Index ofVictims Index 犠牲 block ofVictims Index Ａ地区牲ＡＢ 1000 1000 者Ｅ者Ｂ地区数ＣＣ地区 Index of 数潜在的犠牲者発生指数Potential Victims のＦＤ地区ＣＡのＥ地区 High Risk リ指ス指Ｆ地区Ｅ標Ｂク標 f=ｆ＝Σ潜在的犠牲者発生指数Σ Index of Potential Victims 増 Flood areas are ＤＤ × Frequency×頻度×被災確率 × Probability ■例）潜在的犠牲者発生指数 divided into blocks by Ｅ considering land Category by Risk Scale 0 0 リスクの大きさに応じて feature such as bank High Middle Low High Middle Low Ｆ 1高頻度 10中頻度低頻度 100 1000 1高頻度 10中頻度低頻度 100 1000 カテゴリー分類 Probability Probability Probability Probability Probability Probability of river, road, railway. Recommendation4. Importance of Flood Risk Assessment 6. Japan's response to climate change ‐ Evaluation of risks and programming adaptation measures

Programming based on considering evaluation items, alternates and costs in each and mutual drafts

■ Index of potential casualty ■Index of economic damage Necessity of considering 【Image】【Image】 multiple index of affection

ＡＢＡＢ Example of Affection Index ＣＣ Affection Index ｆ・Potential Casualty Ｄ・Economic Damage Ｄ

High Risk ＥＥ・Administrative Services Depression High Risk Ｆ・Inundate House Ｆ・Environmental Damage

After adaptation measures After adaptation measures

Maximize target function under restriction of assessment評価項目や適応策などに関する制約条件 contents and adaptation measures etc. の下で目的関数の最大化を図る

ｆ１：Current Affection Index ｆ２：Affection Index after adaptation measures Δｆ＝ｆ1－ｆ 2 ｎｎ Δｆ：Reduction of Affection Index by adaptation measures αi ：Weighting factor of each assessment Affection Index Σα i・Δｆ i ／ ΣCi i i n ：Targeted evaluation items Ｃ：Cost Recommendation4. Importance of Flood Risk Assessment 6. Japan's response to climate change ‐ Evaluation Risks and Programming adaptation measures

Expression effectiveness of risk reduction by adaptation measures by color difference

Bank Improvement

ST flood fighting station ＢＡＡ New Road Ｂ Bank Bank of Ｃ Adaptation Measures Road and Railway Ｃ

ＤＥ

Risk reduction Ｆ by adaptation measures ＤＥＰ Index of potential casualty drain pump High Risk ＦＰ medium and small size rivers Recommendation5. Appropriate combination of practical measures 6. Japan's response to climate change ‐ Adaptation measures by using structural method

Improvement of the credibility of structure, effective and multipurpose and long-life utilization of existing structure

Improvement structure improvement of the

International Multipurpose retarding basin 横浜国際総合：鶴見川多目的遊水地of Tsurumi River credibility of structure Stadium Yokohama Final競技場 game of the World Cup was held 越（ex Coastal protection） in 2002 流Overflow 鶴 levee 堤 Tsurumi見 River川

遊水地 tide gate Before 排水門

鳥山川Karasuyama River

aging revetment Multipurpose retarding basin by deteriorated concrete of Tsurumi River

After

River improvement of Rehabilitation of aging revetment flood control（Dam） Tsurumi river by setting up anterior wall Recommendation5. Appropriate combination of practical measures 6. Japan's response to climate change ‐ Adaptation measures by using regional development

Response to floods that cannot be dealt with by facility-based measures, through land use or community development allowing inundation.

Shift to land use or ways of living that minimize damage circle levee River improvement of continuous levee

River improvement for protection of specified areas by using circle levees Designation of potential disaster hazard area

Restrictions on land use by designating potential disaster hazard areas Shift to community planning resistant to inundation

Class 4 disaster Sample ordinance restrictions (Nagoya City) hazard area Class 3 disaster hazard area １階の床の高さ構造制限図解 *建築物の建築禁止範囲…海岸線・河岸線から N・P 50m以内で市長が指定する区第市 5 域１街 4 1階床高制限…居住室を有する建築 3 種化Ｎ・Ｐ（+）4m以上木造禁止物、病院及び児童福祉施設等区区（ｍ）の建築禁止域域木造以外の構造で、居住室等の床の高さをN・P（+）5.5m以上としたものについては建築可能第市 2階以上に居室設置 N・P *公共建築物の制限２街緩和：延べ面積が100㎡2 （第2種～第4種区域）種化Ｎ・Ｐ（+）1m以上以内のものは避難 1 1階床高範囲…学校、病院、集会場、 Class 2 disaster 区区室、避難設備の設 0 官公署、児童福祉施設等その hazard area 域域置による代替可（ｍ）他これらに類する公共建築物第市 N・P 制限…1階の床の高さN・P（+）３街 2mかつN・P（+）3.5m以上の居 2 種化Ｎ・Ｐ（+）1m以上 1 1階床高室設置区区 0 域域（ｍ） Class 1 disaster 市 hazard area 第街 N・P ４化 2 種調Ｎ・Ｐ（+）1m以上 2階以上に居室設置 1 1階床高区整 0 域区（ｍ） Adopting pilotis to prevent damage to buildings during a flood 名古屋市臨海部防災区域図域 Recommendation5. Appropriate combination of practical measures 6. Japan's response to climate change ‐ Adaptation measures centering around risk management

Building of a wide-area disaster prevention network that connects Reinforcement of actions in the initial stages of a embankments, roads on the dry river bed for emergency traffic and disaster for minimizing damage and restoring elevated roads to wide-area disaster prevention bases. infrastructure early, and enhancement of an organizational setup to achieve the goal Technical Emergency Control Force (TEC-FORCE) 《緊急災害対策派遣隊》TEC-FORCE Organizational体制 setup 構成員 Staff of Regional各地方整備局・事務所職員 Development Bureaus and Offices 現地支援センターField support center Engineers of National Institute for Land and 広域基盤施設部隊 Infrastructure国総研・土研等の技術専門家 Management and Public Works Research Wide-area infrastructure force Institute (rivers, roads, sediment control, 〈河川・道路・砂防・港湾等〉ports, etc.) 技術支援グループ（技術専門家）Technical support group (engineers)

契約 Contract/ Private sector construction organizations Sewerage system force agreement 下水道部隊協定民間建設関連（資機材の操作員）(operators of equipment)

Building宅地部隊 land force Coordination連携

建築物部隊 Staff地方公共団体職員 of local public entities Buildings force

Network of roads and river embankments Activities -Investigation of damage -Quick repairing -Prediction of degree of damage risk

-Planning of control Drainage pumping vehicle measures -High-level technical guidance -Assistance in reconstruction Inundation of Route 34 during a Disaster control helicopter flood in July 1990 Image of road-embankment connection Recommendation5. Appropriate combination of practical measures 6. Japan's response to climate change ‐ Adaptation measures based on risk management

Share preliminary information concerning the degree of flood risk

Water洪水ハザードマップの作成イメージ levels in built-up areas in the past floods are indicated on the hazard map.

Information dissemination Flood hazard map of xx City channel Locations and names of shelters

Points of contact -Administrative organizations -Medical institutions -Lifeline systems management organizations

Underground space

Toyooka City, Hyogo Prefecture Flood Embankment Shelter (building)

Potential inundation Image of a flood hazard map Hints on escape and areas and depths of necessities inundation Easily recognizable signs Recommendation5. Appropriate combination of practical measures 6. Japan's response to climate change ‐ Adaptation measures based on risk management

Share real-time information

・ Provision of rainfall amounts and water levels real-time via cellular phone, the Internet or local disaster prevention radio ・ Flood forecasting through real-time simulation

Rainfall measurement station Radar observation station

Rainfall measurement station Radar precipitation prediction

Relay station

Delivery of an image to a TV screen Gauging station Information provision via cellular phone or personal Gauging computer station

Flood alarm Surveillance office camera

Flood (water level) River office prediction system

Meteorological observatory

Floodwater prediction through real-time simulation 6. Japan's response to Considerations to be taken for implementation climate change (1) Inter-governmental efforts (2) Promotion of cooperative work with the public (3) Priority investment in preventive measures (4) Clear prioritization (5) Preparation of road maps (6) Adoption of a flexible approach (7) Cooperation with related organizations (8) Developing new technologies and contributing to the international community (9) Promotion of research and application of their results to plan flood control, water use, and environmental conservation 6. Japan's response to Future timeline for implementation of this study climate change

Revising adaptation measures by analysis of water-related disaster risks with improvement of flood prediction by monitoring changes of climate change and social condition.

Range of 水 Monitoring prediction

Flood Risk 災害 Accuracy リ enhancement Reduction risks by ス adaptation measures Range of ク prediction 【 Phase Ｉ】【PhaseⅡ】・Examination about improvement of adaptation measures ・Evaluation of Phase I activity ・Make road map ・Implementation adaptation measures by result of evaluation ・Drawing up adaptation measures ・Revise the road map Now 5 years later Introduction on adaptation measures in Tsurumi river 8. Adaptation measures Outline of Tsurumi River (Geography) in Tsurumi River

Hill / tableland 70％ Tokyo Chiba Pref. Alluvial lowland 30％ Kanagawa Tsurumi river basin Pref. Riverbed gradient : 1/250

Middle section with stepped cross section

Tsurumi River

Tsurumi Densely-populated River downstream section elevation Hayase- Tsurumi Onda River River River 0～20m

Toriyama River

Upstream section Riverbed gradient ：1/1,000 below grand level 8. Adaptation measures Outline of Tsurumi River (Urbanization and population increase) in Tsurumi River

Urbanization ration has increased Rapid economic growth has turned natural area into urban area by 75% in 50years 1958 10％ 1958 10 1966 20%

Typhoon Karinogawa in Sep 1958 450,000 700,000

1975 60% Present 85%

Typhoon No.17 in Sep 1976 1,200,000 1,880,000

Natural Area Urbanization Urbanization Population Urban Area 8. Adaptation measures Outline of Tsurumi River (Effect of urbanization) in Tsurumi River

・Population increased by Function of keeping and retarding water became weakened 1.4 million in 50 years

・85% of river basin area urbanized

・Typical urban river

Before development After development As a result Slight urbanization Significant urbanization 1,300 m3/s Peak runoff Volume Doubles ・Discharge into river Difference 770 m3/s has become faster Present Runoff reaches ・Peak runoff has Before its peak in becomes bigger Development 1/3 of time

2～3 hours 10 hours Basic strategy for controlling inundation damage 8. Adaptation measures (Runoff allocation) in Tsurumi River Runoff allocation by target rainfall Peak runoff without discharge control ･･･2,110m3/s Allocation in river basin： 250m3/s Existing and newly developed rainfall 3 storage and infiltration facilities 205m /s Rainfall storage and infiltration measures 3 by municipalities 15m /s Rainfall storage tubes by sewerage 3 administrators 30m /s Allocation in river：1,860m3/s Controlled by rivers 1,500m3/s Storage in flood control facilities 3 and in retarding basins 360m /s

※Under the future land use, runoff is estimated at Sueyoshibashi point based on the largest rainfall after 1945. 8. Adaptation measures River related projects in Tsurumi River Basin inundation control plan in Tsurumi River

Future flood control

Existing retarding basin

【Administrator】 MLIT Tokyo Metropolitan Kanagawa Prefecture Yokohama City 8. Adaptation measures Sewerage projects in Tsurumi River Basin inundation control plan in Tsurumi River

Natural drainage area

Pump drainage area (Name)

Rainwater storage tube (Name) 8. Adaptation measures Rainwater storage facilities in Tsurumi River Development of facilities for target rainfall

Planned discharge in pump drainage areas Planned storage of major facilities City Discharge Planned City Storage facility Planned area discharge Storage Yokohama Tsuzuki 17m3/s Yokohama Shin hasue trunk line 410,000m3 3 Kouhoku 142m /s Kozukue chiwaka trunk line 256,000m3 3 Hokubu 189m /s Kawasaki Shibukawa rainwater storage 144,000m3 Kawasaki Kase 55m3/s tube Egawa rainwater storage tube 81,000m3 Total 402m3/s

Pump facilities Rainwater storage tube 8. Adaptation measures Storage, infiltration and forest conservation in Tsurumi River Development of rainwater storage and infiltration facilities, conservation of forested areas (Total effect by municipalities : 0.3 million m3)

Storage Storage facilities in schools, Infiltration Infiltration by permeable pavement parks and public houses

Infiltration Inlet Infiltration trench

Forest Conservation Infiltration Inlet Infiltration trench

◆Purchase and conservation of forest in developing area 8. Adaptation measures Operation rule of pumping station in Tsurumi River

Preparation of basic operation rules, communication, command and control, information sharing and public announcement

Basic rules of restricted pump operation 《Image of flood damage by drainage pump》 -River and sewerage administrators make basic rules of restricted pump operation to Drainage with a P effectively decrease urban flood and pump P inundation caused by heavy rainfall that P Sewer exceeds the current project design target.

Ｐ:Drainage pump Communication and information sharing River Although surface water damage along river is mitigated by pump drainage, river water flood may -Related organizations jointly establish occur at the bottle neck of water way in the downstream communication system for effective and efficient pump operation. Stopping -The administrators provide hazard drainage with P a pump P information beforehand and ask for P cooperation from residents. When pump Sewer operation is restricted, the administrators supply necessary information for residents’ River Ｐ :Drainage pump smooth evacuation. Surface water damage may occur around the drainage pump due to drainage restrictions 8. Adaptation measures Public awareness to mitigate damages in Tsurumi River (Public awareness and education on disaster preparedness)

To organize local meetings and raise public awareness on preparedness on disaster Education for pupils Disaster preparedness caravan

Annual educational course To visit local meetings and for pupils on disaster explain to residents preparedness at the Center Tsurumi River Administration Center 8. Adaptation measures Public awareness on flood damages in Tsurumi River (Advance dissemination of flood and inundation prone information) By simulating urban flood and inundation, municipalities prepare “Hazard Maps”

Urban flood prone area Urban inundationハザードマップ prone area （River administrator） (Sewerage administrator) （自治体） Flood is estimated by levee break Inundation by insufficient drainage or overtopping. O capacity is estimated. n

th e b a s is

“Hazard Map” released by Yokohama City 8. Adaptation measures Other measures (follow-up the plan) in Tsurumi River

Implementation, monitoring, evaluation and modification of the plan

Progress of major projects ・Implementation of river and sewage project Installation of rainwater storage and infiltration facilities

・Installation of rainwater storage and infiltration facilities ・Countermeasures against blocking rainwater infiltration ・Progress of rainwater storage and infiltration facilities constructed for development based on regulations and guidelines

Changes of river basin ・Re-evaluation of latest development (area, location, type etc.)

Modification of the plan International Activities 7. International Contribution to International Organization Activities

Contribution to WMO/GWP Contribution to WMO/ESCAP (the Associated Programme on Flood Management) Typhoon committee ● Purpose of Guideline Technical contribution to hydrological component ・ Sustainable development considering flood in terms of reduction of typhoon damages in asia- risks which are changed by development pacific region ・Maximized social benefit in flood prone area for reduction of social vulnerability 2 regional incorporation programme (RIP) (Hazard Map ・Minimized loss of life and Landslide Warning System) are ongoing and ・Conservation of environment holding workshop

Contribution to WWAP (World Water Assessment Programme) WWAP from phase I in Oct 2000 to ongoing phase III, Since Japanese government strongly support WWAP financially and technically

Contribution to UNESCO’s IRBM (Integrated River Basin Management) Japanese expert who related in WMO contribute to APFM which is producing IFM (Integrated MLIT, JWA, ICHARM contribute their expertise and Flood Management) guideline (2002～) technology

Increasing External Forces and Impacts on Regional Climate Models (RCM20 and GCM20) Land and Society

Coupled Atmosphere-Ocean-Sea Ice Model The recently developed simulation model enables for the Earth Simulator (CFES) Spatial resolution more detailed regional climate prediction. Atmosphere: 280 km x 280 km (30 layers) Ocean: Longitude 2.5 degrees/Latitude 0.5 to 2.0 degrees (23 layers) Regional Climate Models

GCM20 RCM20 (General Circulation Model) (Regional Climate Model)

Areas to be Japan and Global scale Climate model for Asia Calculated surrounding areas 60 km x 60 km Horizontal About 20 km About 20 km (36 layers) Resolution Number of meshes Number of meshes 1920 x 960 129 x 129 Number of Vertical 60 layers 36 layers Layers Lateral Boundary N/A, as this is a Climate model for Conditions global scale model. Asia Climate model for Japan

20 km x 20 km (36 layers)

Concept of lateral boundary conditions of RCM20