Adaptation Strategy for Climate Change in Japan - Toward Water-disaster Adaptive society - October 23, 2008 Toshio OKAZUMI Director for International Water Management Coordination Ministry of Land, Infrastructure, Transport and Tourism Japanese Government 1. Present conditions Japan is vulnerable to climate change and issues

Kinki Region Kanto Region A

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Station R n Ueno a

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Kanzaki River K u Kameido R a m nd i

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Amagasaki Ri i Station

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Station Shin-Osaka Station a r

Tokyo Shinjuku R Kinsicyo

Old Edo River

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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 the population and

3m – 4m 3m – 4m 1m – 3m about 75% of the property on 1m – 3m 0m – 1m 0m – 1m -1m – 0m -1m – 0m -1m – about 10% of the land which is -1m – Water Area Water Area lower than the river water level during flooding 1. Present conditions Recent flood disasters in Japan and issues

2008.7.28 Flood in Hyogo Pref. 2008.8.29 Flood in Aichi Pref. largest-ever rainfall per Water level rapidly rose hour Amount rainfall per hour by 134cm in 10 min. 雨量 Amount rainfall per hour Cyunichi New Paper

160

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120 100 146mm/h 80

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0 Cyunichi New Paper 1516171819202122232412345678910

Break Point 1. Present conditions Recent rainfall trend and issues Annual total of hourly rainfall events (Source: approx. 1,300 AMeDAS locations across Japan) 1. Number of events of 50 mm or more rainfall per hour 500 (instances/year) 400 300 200 1996~2005 100 1976~1985 1986~1995 Average events Average events Average 234 events 228888 209209 234 ‘04 01976 ‘77 ‘78 ‘79 ‘80 ‘81 ‘82 ‘83 ‘84 ‘85 ‘86 ‘87 ‘88 ’89 ‘90 ‘91 ‘92 ‘93 ‘94 ‘95 ‘96 ‘97 ‘98 ‘99 ‘00 ‘01 ‘02 ‘03 ‘05 2. Number of events of 100 mm or more rainfall per hour 10 (instances/year) 1976~1985 1986~1995 1996~2005 Average 4.74.7 events Average 22.22 events Average 2.22.2 events 5

0 1976 ‘77 ‘78 ‘79 ‘80 ‘81 ‘82 ‘83 ‘84 ‘85 ‘86 ‘87 ‘88 ‘89 ‘90 ‘91 ‘92 ‘93 ‘94 ‘95 ‘96 ‘97 ‘98 ‘99 ‘00 ‘01 ‘02 ‘03 ‘04 ‘05 2. Impacts of climate Mechanism of global warming and climate change change

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

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 stormstorm surgessurges andand coastalcoastal MoreMore frequentfrequent MoreMore seriousserious debrisdebris flowsflows HigherHigher riskrisk ofof droughtsdroughts erosionserosions floodsfloods 2. Impacts of climate Estimation of increased rainfall in each region change

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 2. Impacts of climate Decreasing degree of safety level change

Impact for flood safety level by changing rainfall after 100 years Increasing future rainfall decreases the 1/200 （CurrentTarget ） 1/150（CurrentTarget） 1/100（CurrentTarget ） （annual exceedance probability） （ degree of safety against floods. 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 ※ The circled numbers indicate the number of calculated river systems. 石狩川 (北海道） 2. Impacts of climate Changes of peak runoff by future rainfall change

北上川 Estimated（東北） future rainfalls are about 1.1 to 1.5 times the current rainfall. Peak runoffs are estimated at 1.1 to 1.7 times the current peak runoffs 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. １／１５０ ｋｍ2 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. １／１５０ ｋｍ2 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% 2. Impacts of climate Impacts of sea level rise change Below-sea-level areas in three large metropolitan areas (Tokyo Bay, Ise Bay and Osaka Bay)

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

OsakaOsaka Bay Bay IseIse Bay Bay TokyoTokyo Bay 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 storm surges 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) 577559 879861 1.5 人口（万人）Population (Million) 3.88404 5935.76 1.5 3.Adaptation measures Basic concept of adaptation strategies for 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 storm surges and coastal erosions -Wider range of variation in rainfall intensity and change of river flow regime Frequent and serious droughts

Basic concept for a future ideal society Combining mitigation and adaptation aiming at ‘’ Water -disaster adaptive society’’ Basic direction of climate change adaptation strategies

1. Adaptation measures to achieve “Zero casualty" should be prioritized, because ‘’Zero damage’’ from disasters is virtually impossible. 2. In a nerve center like the Tokyo metropolitan area, intensive efforts should be channeled to prevent core national functions from paralysis. 3.Adaptation measures Adaptation strategies for climate change Countermeasures for Climate Change

Mitigation Measures

Multiple measures

Adaptation Measures Effective & Efficient Program - Risk Assessment - Structures Ex) Dike, Dam, Discharge, Infiltration trench, … Regional Development Ex) Land use regulation, Building restriction, Circle levee, … Crisis Management Ex) Flood Hazard Map, Real-time information, TEC-Force, … Monitoring Ex) River Information, Planning, Revision of plan, … 3.Adaptation measures Multiple measures in response to increasing risk for climate change The red figures indicate the present The blue figures indicate the flood safety levels. Image of flood disaster adaptation measures future flood safety levels. Present Future （For example, after 100 years）

1/150 1/150

Current target flood safety The current target flood Reconfiguration of level safety level would river improvement Adaptation by deteriorate with future for increasing increase of precipitation. Structural measures increase of precipitation. external force

1/70 Target flood Flood safety safety level level Current target flood safety level in 100 presently safety level in 100 1/40 years' time secured 1/20 1/20 Flood safety Deterioration of the flood level secured safety level currently secured

Adaptation measures based on regional development (e.g. land Comprehensive flood control measures use restrictions, review of current land use, etc.) 3.Adaptation measures Process of effective and efficient adaptation program for climate change

① Review past floods ③ ④

②Conduct runoff/flood analysis ⑤ 入間台地 ① ⑥ ③Categorize flooding patterns

②

④Calculate damage and impacts

⑤Plan effective and efficient adaptation measures ② Conduct runoff/flood analysis ③-1 Categorize flooding patterns

e.g. projection of victims bank堤防補強 strengthening

ST disaster prevention 防災ステーションstation Ａ Ａ Ｂ Ｂ Potential Road Potential

victims index Increasing Risks

Increasing Risks Ｃ victims index Ｃ

River 新設するNew road embankment道路盛土 etc Ｄ Ｄ Ｅ Ｅ drainage pump 排水ポンプ Ｐ Simulate the effectiveness ③-2 Zone the categorized Ｆ Ｐ areas (③-1) by rivers, Ｆ of adaptation measures roads, railroads, etc. ④ Translate disaster risks to a ⑤ Plan effective and efficient risk map based on the zones. adaptation measures 3.Adaptation measures Structure-based Adaptation for climate change

Improvement of the reliability of structures, full and long-life utilization of existing structures

Constructing new structures

Flood control dam

High standard embankment Underground discharge channel 3.Adaptation measures Structure-based Adaptation for climate change

Flood control by constructing a road as a secondary levee to prevent the expansion of the damaged area

Inundation in the Aug. 1986 flood Expected effect of secondary levee Levee break ← Yoshida River e ion point rus ruct a onst ←Yoshida River N er C flooding r → Und T ive e R leve → o Flooded ary ver nd T use Ri h eco Nar S o o area flooding h k o u k Flooding u R R area a a Mitigating i i lw l flood damage After 6 w 4 a at city center a 3 R y Residential area y completion Actual flooded area

Rescue effort by helicopter C o

m in Aug. 1986

p l

6 e

4 t 3 e R d

In the 1986 flood, 3,060ha was flooded, 1,510 houses The secondary levee is under construction. The levee were flooded above the floor level, and some parts of will also used as a road. the area stayed under water up to 12 days. 3.Adaptation measures Structure-based Adaptation for climate change - Effective use of existing structures Based on the deep consideration容量振り替えによる既存ダム群の再編成 on the characteristics of a river basin, the re-allocation of a multi-purpose dam’s capacity can be more effective in terms of flood control and water use.

Basin area: large Flow: low Ｂ Flood Control Water Use Dam Water use Water use Flood Control Ａ Ａ Dam Flood Control Present WaterWater Useuseダ Reallocation ム New Capacity Basin area: small Present Reallocation Flow: high

Re-allocation of Multi-purpose dam’s capacity Re-allocation will result in more ●Re-allocation of water use capacity to flood control capacity. effective flood control and ●Capacity allocation among existing and newly- water resource use. planed dams 3.Adaptation3.Adaptation measures measures Adaptation in river basins forfor climate climate change change - Storage, infiltration and forest conservation in river basins Storage Storage facilities in schools, Infiltration parks and public houses

Infiltration Inlet Infiltration trench

Infiltration inlet Infiltration trench Forest Conservation

◆Purchase and conserve forests in developing areas Adaptation measures 3.Adaptation3.Adaptation measures measures forfor climate climate change change in step with local community development Land use and community development allowing space for inundation should be promoted as response to floods that cannot be coped with by structural measures.

Shift to land use and 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 Community planning Building restrictions Floor height of the 1st to cope with inundation Class 4 disaster １階の床の高さstory Structural 構 造 制 限 restriction Illustration図 解 *建築物の建築禁止 *No buildings shall be constructed. hazard area Class 3 disaster 範囲…海岸線・河岸線から Scope --- Areas designated by the hazard area N・P mayor the distance50m以内で市長が指定する区 from which to any 第 市 shore line 域or riverbank line is not 5 longer than制限…居住室を有する建築 50 meters. １ 街 4 1階床高Floor height of Restriction --- Any building having 種 化 Ｎ・Ｐ（+）4m以上 木造禁止 3 物、病院及び児童福祉施設等 N P (+) 4m Wooden structure is the 1st one habitable room or more, hospital, 区 区 ⋅ story welfare facilityの建築禁止 for children, and the or more prohibited. （ｍ） 域 域 like shall not木造以外の構造で、居住室等 be constructed. Any buildingの床の高さをN・P（+）5.5m以 of non-wooden construction may be constructed, Class 1 zone 1 Class provided that上としたものについては建築 the height of the floor of any habitable可能 room, etc. is not less than N⋅P (+) 5.5m or more.

第 市 area promotion Urbanization 2階以上に居室設置 *公共建築物の制限 ２ 街 緩和：延べ面積が100㎡ （第2種～第4種区域） Any habitable room shall be N・P 種 化 Ｎ・Ｐ（+）1m以上located on以内のものは避難 the second story or *Restriction範囲…学校、病院、集会場、 on public buildings 区 区 higher. 室、避難設備の設 官公署、児童福祉施設等その N⋅P (+) 1m Relaxation: For a building with a 2 (Classes 2 to 4 zones) 域 域 total floor 置による代替可area no more than 1 1階床高Floor 他これらに類する公共建築物 or more 100m2, the aforementioned height of Scope --- Schools, hospitals, 第 市 restriction may be replaced with 0 the 1st assembly halls,制限…1階の床の高さN・P（+） public offices, welfare Urbanization the provision of an evacuation story promotion area facilities for2mかつN・P（+）3.5m以上の居 children, and other public ３ zone 2 Class 街 room and evacuation equipment. （ｍ） buildings similar室設置 thereto. Class 2 disaster 種 化 Ｎ・Ｐ（+）1m以上 N・P 区 区 Restriction --- The floor height of the hazard area 1st story shall be N⋅P (+) 2m and any 域 域 N⋅P (+) 1m 2 habitable room shall be located at a 1 1階床高Floor 市 or more height of height of N⋅P (+) 3.5m or higher. 0 the 1st 第 街 story Urbanization Urbanization promotion area

４ Class 3 zone 化 （ｍ） 種 調 Ｎ・Ｐ（+）1m以上 2階以上に居室設置 Class 1 disaster 区 整 N・P hazard area 域 区 Any habitable 域 N⋅P (+) 1m room shall be 2 Floor or more located on the 1 height1階床高 of 0 the 1st Piloti-type building to avoid second story or story

Class 4 zone higher. （ｍ） Nagoya City control area Urbanization damage during flooding Adaptation measures 3.Adaptation measures in step with local community development for climate change More local governments established ordinances including the designation of disaster hazard areas (DHA) for cost and time-effectiveness

Conceptual Maps The total number of DHA-designation ordinances by local government Continues levee 災害危険区域の指定に関する条例を制定した自治体数（累計）

2006 Subsidy was2006 expanded 土地利用一体型水防災事業に名称変更。 to construction 浸水防止施設、貯留施設の整備も対象 of floodwall and retention facilities.

2001 Designation2001 of disaster 水防災対策特定河川事業に名称変更。 hazard 災害危険区域の指定が要件に areas was required for subsidy. 0 Substantial cost and time are necessary to complete 1 2000 Subsidy was 2000expanded 流域水防災対策事業に名称変更。 to construction 5 0 30 宅地嵩上げ、横堤も対象に 0 2 0 0 of house lot raising and cross dykes. 0 2 25 5 0 9 2 1995 New subsidy 1995for flood田園地域集落治水事業創設 control in 0 9 20 （連続堤によらない治水対策）9 1 limited areas was created. 5 9 8 1 Ring levee 15 0 9 New scheme of flood 8 1 5 9 control measures based 10 7 1 0 9 on land use 7 1 5 5 9住居の移転を促進することが適当でない区域が対象Targets were only areas 6 1 0 0 9 where houses could not 6 1 5 9 be relocated. 5 1 0 9 5 1 9 House lot raising 1 （西暦）

New countermeasures linked with land use can be 注）上記は、指定理由が「出水」を含む災害危険区域に関する条例を制定した自治体数の年度別推移 implemented faster (e.g. ring levee, house lot raising) A new concept for urban development： 3.Adaptation measures Compact community easier to implement flood control measures for climate change Compactly-built residential areas provide better energy efficiency and easier environment for flood control projects

Present city

Disorderly-spread city

Houses relocated to this area Future picture

Compact city harmoniously surrounded by nature r ve Ri Green and Agricultural Urban area where people a Oy area with residences can reside and make a living

Urban Pond center Suburb area where people can enjoy affluent life

Suburb iver ai R Kok Urban center Suburb Green area Green area Forest Agri field イメージ Rural Settlement Hakojima retarding basin Image of compact city in Tohoku region (constructed in 1990) A new concept for urban development: 3.Adaptation measures urban development for a low-carbon, water-disaster adaptation society for climate change Urban development should be promoted to build a low-carbon society which is also resilient to floods.

Integrated project (Lake Town Development Project) Motoarakawa Riv. Construction of a regulating pond channel Driving Land relocation as a flood control project Regulating pond project ＋

Urban development by Nakagawa Riv. a land relocation project Large-scale regulating pond Plus adaptation

Project to reduce CO emission 2 Driving by 20% from the town Channel

UrbanUrban renovationrenovation withwith bothboth mitigationmitigation andand adaptationadaptation Adaptation measures 3.Adaptation6. Japan's measuresresponse to for climateclimate changechange with emphasis on crisis 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 evacuation areas and depths and necessities Easily recognizable signs Adaptation measures 3.Adaptation6. Japan's measuresresponse to for climateclimate changechange with emphasis on crisis management Share real-time information ・ Real-time dissemination of rainfalls and water levels via cellular phone, the Internet or local disaster management radio communications systems ・ Flood forecasting through real-time simulation

Rainfall measurement station Radar observation station

Rainfall measurement station Radar precipitation prediction

Relay station

Provision of flood-related Gauging station Information dissemination images for TV broadcasting via cellular phone or Gauging personal computer station

Flood alarm Surveillance office camera

Flood (water level) River office prediction system

Meteorological observatory

Floodwater prediction through real-time simulation Adaptation measures 3.Adaptation measures for climate change with emphasis on Capacity Building & Public Awareness Efforts should be made to organize local meetings and raise public awareness toward disaster preparedness.

Education for school children Disaster preparedness workshop

Annual educational course A workshop team visits a for school children on neighborhood group and explains disaster preparedness at the about disaster preparedness. Center (right photo) Tsurumi River Administration Center Adaptation measures 3.Adaptation6. Japan's measuresresponse to for climateclimate changechange with emphasis on crisis management Reinforcement of actions in the initial stages of a disaster to minimize damage, restore infrastructure quickly, and enhance organizational set-ups to achieve the goals. Emergency helicopter TEC-FORCE started in 2008 (Technical《緊災害策派 Emergency Control》 Force)

Organizational体制 setup 構成員 Staff of 各地方整備局・事務所職員Regional Development Bureaus and OfficesDrainage pumping vehicle 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 Activities Wide-area infrastructure force Institute (rivers, roads, sediment control, ports, etc.) 〈河川・道路・砂防・港湾等〉 技術支援グループ（技術専門家）Technical support group (engineers) -Damage assessment

契約 -Quick repairing 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) -Prediction of degree of

宅地部隊 Coordination damage risk Building land force 連携 建築物部隊 -Planning of control measures Staff地方公共団体職員 of local public entities Buildings force -High-level technical guidance -Assistance in reconstruction Conclusion ①Prioritized investment in disaster prevention 9Investment should be prioritized in areas related to disaster prevention due to limitation of available capacity ②Clarification of priorities and development of road map 9Prioritized measures should be clarified to draw up short-term, middle-term, long-term policies. 9A road map should be developed to complete flood control using multiple measures (e.g. structure, land-use, preparedness) based on disaster risk assessment. 【 】 ③Adoption of flexible approach Flexible Approach Adaptation measures should be flexibly revised ：気象変動Prediction by climate change 9A flexible approach should be adopted, in which the based on analysis of water-related disaster risks の予測値

using improved flood prediction methods by which ：適応策Reductionに risks road map should be revised in response to future impacts of climate change and social conditions よってby adaptation低減 されるリスク observation and accumulated knowledge. are constantly monitored.

モニタリングMonitoring Monitoring モニタリング Monitoring モニタリングMonitoring 水 予測のRange of範囲 ④New technical development and モニタリング prediction Flood Risk 災 Accuracy global contribution 害 enhancement精度の向上 9Japan will contribute to the world by transferring our Range of リ prediction予測の範囲 ス 精度の向上 new technologies, expertise, and policies. Range予測の of範囲 適応策策定Drawing up prediction ク Adaptation ⑤Participatory approach measures 9Participatory approach is necessary. Citizens Revising Revising Revising Adaptation適応策見直 し 適応策見直Adaptation し Adaptation should be well informed, and policy makers should measures measures 適応策見直measures し have opportunities to get feedbacks from citizens. Past過去 Now現在 Future 未来 Introduction to adaptation measures in Tsurumi River 7. Adaptation measures Outline of Tsurumi River (Geography) in Tsurumi River

Hill / tableland 70％ Riverbed gradient : 1/250 Alluvial lowland 30％

Middle section with stepped cross section Tsurumi River

Densely-populated Tsurumi

River downstream section

elevation Hayase- Tsurumi Onda River River River 0～20m

Toriyama River

Upstream section Riverbed gradient ：1/1,000 below ground level 7. Adaptation measures Outline of Tsurumi River (Urbanization and population increase) in Tsurumi River

Urbanization rate has increased Rapid economic growth has turned a 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 7. Adaptation measures Outline of Tsurumi River (Impacts of urbanization) in Tsurumi River

Basin function of keeping and retarding water has become ・Population increased by weakened. 1.4 million in 50 years.

・85% of the river basin area was urbanized.

・Tsurumi became a typical urban river

Before development: After development: As a result Slight urbanization Significant urbanization 1,300 m3/s Peak runoff volume Doubled ・Discharge into river Difference 770 m3/s has become faster. Present Runoff reaches ・Peak runoff has Before its peak in become greater. Development 1/3 the time.

2～3 hours 10 hours Basic strategy for controlling inundation damage 7. Adaptation measures (Target rainfall to prevent urban flooding) in Tsurumi River

River improvement goal: Discharges caused by the following rainfalls run down the river safely. Section administered Section administered by central government by local government Largest rainfall after 1945 ：343mm/2days Rainfall in a return period of 10years : 60mm/hour Rainfall recorded by typhoon Karnogawa in Sep 1958 Rainfall which may occur once in 10 years

Shikouji River Asou River

Local Gov Yagami River

Hayase River Tsurumi River Local Gov Local Gov Local Gov Ookuma River Local Gov Onda River Local Gov Tsurumi River Local Gov

Umeda River Sunada River Local Gov Designated urban river Targeting the largest flood in Sep 1958 Karasuyama River Targeting rainfall in a return period of 10years Basic strategy for controlling inundation damage 7. Adaptation measures (Target rainfall to prevent urban flooding) in Tsurumi River Sewerage improvement goal : To prevent inundation damage caused by the following rainfalls Pump drainage area Natural drainage area

Rainfall in a return period of 10years : 60mm/hour Rainfall in a return period of 5years : 50mm/hour Rainfall which may occur once in 10 years Rainfall which may occur once in 5 years

Natural drainage area

Pump drainage area

Kawasaki city Natural drainage area Pump drainage area

Rain water is Sewers are located naturally drained below the river or sea through sewers. level. Rain water is drained by pumping. Yokohama city Basic strategy for controlling inundation damage 7. 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 installed by sewage 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. 7. Adaptation measures River-related projects in Tsurumi ririveverr basin inundation control plan in Tsurumi River

Future flood control Tokyo Chiba Pref.

Kanagawa Tsurumi river basin Existing retarding basin Pref.

【Administrator】 MLIT Tokyo Metropolitan Kanagawa Prefecture Yokohama City 7. Adaptation measures Sewerage projects in Tsurumi river basin inundation control plan in Tsurumi River

Tokyo Chiba Pref.

Kanagawa Tsurumi river basin Pref.

Natural drainage area

Pump drainage area (Name)

Rainwater storage tube (Name) 7. 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 7. Adaptation measures Storage, infiltration and forest conservation in Tsurumi River Development of rainwater storage and infiltration facilities, and conservation of forest 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 conserve forests in developing areas 7. Adaptation measures Operation rules of pump stations 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 P effectively mitigate urban flood and pumps 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 a 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 pumps 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 7. Adaptation measures Public awareness to mitigate damages in Tsurumi River (Public awareness and education on disaster preparedness) Efforts should be made to organize local meetings and raise public awareness toward disaster preparedness. Education for school children Disaster preparedness workshop

Annual educational course A workshop team visits a for school children on neighborhood group and explains disaster preparedness at the about disaster preparedness. Center (right photo) Tsurumi River Administration Center 7. 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-proneハザードマップ area （River administrator） (Sewerage administrator) （自治体） Flooding is assumed to occur due Inundation is assumed to occur due to levee break or overtopping. O to insufficient drainage capacity . n

th e b a s is

“Hazard Map” released by Yokohama City 7. 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 projects 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 urban development based on regulations and guidelines

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

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

Contribution to WMO/GWP Contribution to WMO/ESCAP (the Associated Programme on Flood Management) Typhoon Committee ● Purposes of Guideline Technical contribution to the hydrological ・ Promote sustainable development considering component in terms of reduction of typhoon flood risks which are affected by development. damage in the Asia-Pacific region ・Maximize social benefits in flood-prone areas for reduction of social vulnerability. Two regional incorporation programmes (RIP) (Hazard ・Minimize the loss of life. Map and Landslide Warning System) are ongoing and ・Conserve the environment. holding workshops.

Contribution to WWAP (World Water Assessment Programme) Japan has contributed to WWAP from phase I in Oct 2000 to ongoing phase III. Japanese government strongly support WWAP financially and technically. Contribution to UNESCO’s IRBM (Integrated River Basin Management) Japanese experts working for WMO contribute to APFM, which is producing the IFM (Integrated MLIT, JWA, ICHARM contribute their expertise and Flood Management) guideline (2002～). technology to IRBM.