Adaptation Strategy for Climate Change in Japan - Toward Water-disaster Adaptive society -

Transcription

1 Adaptation Strategy for Climate Change in Japan - Toward Water-disaster Adaptive society - September 22, 2008 Toshio Okazumi Director for International Water Management Coordination Ministry of Land, Infrastructure, Transport and Tourism Government of Japan

2 Japan is vulnerable to climate change Kinki Region 1. Present conditions and issues Kanto Region Amagasaki Station Yodo River Shin-Osaka Station Osaka Station Osaka Castle Tennouji Station Kanzaki River Neya River Hirano River Ikebukuro Station Shinjuku Station Shibuya Station Tokyo Station Ueno Station Kanda River Shibuya River Meguro River Sumida River Tone River Ayase River Ara River Shinnaka River Kameido Station Kinsicyo Station Old Edo River Elevation Elevation 3m 4m 1m 3m 0m 1m -1m 0m -1m Water Area About 50% of population and about 75% of property on about 10% of land lower than water levels in rivers during flooding 3m 4m 1m 3m 0m 1m -1m 0m -1m Water Area

3 2008 Floods in Japan 1. Present conditions and issues Floods in Hyogo Pref Floods in Aichi Pref. Rapid water level rise of 134cm in 10 minutes largest-ever amount rainfall per hour (146mm/h) Amount Amount rainfall rainfall per per hour hour Break Point

4 Increase of torrential rain 1. Number of instances of 50 mm or more rain in an hour (instances/year) 1976~1985 Average288 instances Average 209 instances Average 234 instances ~ Number of instances of 100 mm or more rain in an hour (instances/year) 1976~1985 Average2.2 instances 1986~1995 Average 2.2 instances Annual total of hourly rainfall instances (from approx. 1,300 AMeDAS locations across Japan) 1996~ Present conditions and issues 1996~2005 Average 4.7 instances Data from the materials prepared by the Meteorological Agency 04 05

5 Mechanism of global warming and climate change 2. Impacts of climate change Large volumes of greenhouse gas emissions cause CO 2 concentration in the air to rise and increase heat absorption, resulting in temperature rise. Thus, global warming occurs. Melting of glaciers, ice caps and ice sheets Thermal expansion of sea water Change in evapotranspiration Change in snow accumulation condition Sea level rise (Maximum rise: 59 cm) More intense typhoons Increase of precipitation by a factor of 1.1 to 1.3* More frequent heavy rains and droughts Earlier snow melt and reduction of discharge Increase of river flow rate Change in water use pattern More frequent high tides and coastal erosions More frequent floods More serious debris flow Higher risk of drought

6 Estimation of increased rainfall in region 2. Impacts of climate change Future rainfall amounts were projected as a median value in each region of Average rainfall in period Average rainfall in period The above equation was obtained based on the maximum daily precipitation in the year at each survey point identified in GCM20 (A1B scenario). Hokkaido Tohoku Kanto Hokuriku Chubu Kinki Southern Kii San-in Legend Setouchi Southern Shikoku Kyushu

7 Impacts of precipitation 100 years from now on safety against flood 2. Impacts of climate change Precipitation 100 years from now is projected to be about 1.1 to 1.3 times the present level. The highest projection may be 1.5 times. Safety Impacts of precipitation 100 years from now on safety against flood Highest Lowest Present plan 1.1 times 1.2 times 1.3 times 1.5 times Present plan 1.1 times 1.2 times 1.3 times 1.5 times Present plan 1.1 times 1.2 times 1.3 times 1.5 times Safety in present plan: 1/100 Safety in present plan: 1/150 Safety in present plan: 1/200 The safety designated in the present plan would substantially deteriorate based on the assumption of projected precipitation 100 years from now. More frequent inundation and flooding

8 Changes of peak runoff by future rainfall 2. Impacts of climate change Estimations of future rainfall are about compare to current rainfall. Peak runoff will be estimated about compare to current peak runoff in 9 major rivers. Design Rainfall Ishikari Riv. Design Level (Hokkaido) Basin Area 12,697 2 Peak Runoff of Design Flood 18,000 m 3 s 20,500 23,000 25,600 30,700 Kitakami Riv. (Tohoku) 7, ,600 m 3 s 15,700 17,800 19,900 24,000 Tone Riv. (Kanto) 5,114 2 About 21,000 m 3 s (Calculated by 1/200) 23,600 25,900 27,900 31,800 Kurobe Riv. (Hokuriku) ,200 m 3 s 8,100 8,900 9,700 11,300 Izumo Riv. (Cyubu) ,000 m 3 s 9,000 9,900 10,900 12,800 Kinokawa Riv. (Kinki) 1, ,000 m 3 s 17,600 19,700 21,600 25,400 Oota Riv. (Cyugoku) 1, ,000 m 3 s 13,100 14,700 16,300 19,400 Naga Riv. (Shikoku) ,200 m 3 s 12,800 14,500 16,100 19,300 Kase Riv. (Kyusyu) ,400 m 3 s 3,800 4,100 4,500 5,300

9 Frequent and more serious droughts: Deterioration of safety against droughts 2. Impacts of climate change There has been a smaller rainfall amount in recent years and the range of variation has been lower than in the late 1940s through the late 1960s when dams and other facilities were constructed. As a result, stable water supply using dams has been decreasing. Example in the Kiso River system In recent years (in 1979 through 1998): Reduction of water supply below the design level by about 40% Worst drought in recent years (1994): Reduction of water supply below the design level by about 70% Annual precipitation (mm/year) Trend Average Dam and other facilities Reduction by about 40% Reduction by about 70% Year of drought Design water supply Possible stable supply (February 20) Worst drought in recent years (1994)

10 More frequent and serious droughts 2. Impacts of climate change Comparison between present water volume and predicted water volume 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 puddling in paddy fields, may be deteriorated to water use for rice farming. Comparison between present conditions(1979 to 1998) and future rainfall(2080 to 2099) in Class A river Water volume means the sum of snowfall and rainfall reaching to the earth s surface. Legend Future water volume/present water volume Future water volume/present water volume < Future water volume/present water volume < 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

11 Frequent and more serious droughts 2. Impacts of climate change In the upper Tone River, snow cover is likely to decrease considerably. That will accompany the reduction of river flow rate in the snow melt season or in early spring. With global warming, (i) earlier snow melt and (ii) reduction of snowfall induce changes in river flow rate, and (iii) earlier surface soil puddling in paddy fields is expected to cause the annual water demand pattern to change and to have serious impacts on water use. Snow cover (cm) Change in snow cover in 100 years' time due to further global warming (Fujiwara) Average Future October 1 November 1 December 1 January 1 February 1 March 1 April 1 May 1 *Prepared by Water Resources Department, Water and Land Bureau, Ministry of Land, Infrastructure and Transport based on Regional Climatic Model (RCM) 20, a global warming prediction model, developed by Japan Meteorological Agency. (ii) Reduction of river flow rate due to reduction of the amount of snowfall River flow (m 3 /sec) Future (i) Earlier discharge due to earlier snow melt Reduction of river flow during the surface soil puddling in paddy fields Present (iii) Insufficient river flow even when the surface puddling starts earlier (requiring large amounts of irrigation water) Source: Water Resources in Japan 2007, Land and Water Bureau, Ministry of Land, Infrastructure and Transport January April Surface soil puddling period Release of reservoir water not contributing to effective water use Where the reservoir is full, released water is not used effectively. July October

12 Impacts of sea level rise 2. Impacts of climate change 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 Areas with flood risks due to high tides will increase. *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 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 in the case with a one-meter rise of sea level. Present After sea level rise Rate of increase Area (km k 2 ) Population (Million)

13 Basic concept of adaptation strategies 3.Adaptation measures 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 high tides and coastal erosions -Wider range of variation of rainfall intensity and change of river flow regime Frequent and serious droughts Basic concept for Future ideal society Combining mitigation and adaptation aiming at Water -disaster adaptation society Basic direction of climate change adaptation strategies 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

14 Multiple measures for increasing in risk Red figures indicate present degree of safety against flood. Present Image of flood disaster adaptation measures Future For example, after 100 years 3.Adaptation measures for climate change Blue figures indicate future degree of safety against flood. 1/150 1/150 Degree of safety against flood presently aimed at Degree of safety against flood presently aimed at would deteriorate with future increase of precipitation. Reconfiguration of river improvement for increasing external force Adaptation by Structural measures 1/70 Degree of safety against flood presently secured Degree of safety against flood currently aimed at in 100 years' time Deterioration of the degree of safety against flood currently secured 1/40 1/20 Degree of safety against flood aimed at Degree of safety against flood secured 1/20 Comprehensive flood control measures Adaptation measures based on regional development through such actions as restrictions on and review of land use

15 Process of effective and efficient adaptation program 3.Adaptation measures for climate change Review of past flood Runoff analysis and flood analysis Categorize flooding pattern in each category Calculate damage and effect Consider effective and efficient adaptation measures Road River etc Segmentalize flooding patterns of -2Devide flooding patterns into blocks by land features and river Runoff analysis and flood analysis Ex. Prediction of victims Description of disaster risk into Risk Map by blocks -1 Categorize flooding patterns ST bank strengthening New road embankment drainage pump Confirmation effectiveness of adaptation Consider effective and efficient adaptation measures disaster prevention station

16 Adaptation by using structures 3.Adaptation measures for climate change Improvement of the reliability of structures, full and long-life utilization of existing structures Constructing new structures usual Storage facilities flooded D Permeable pavement Infiltration trench and inlet s Underground discharging Channel trench inlet

17 Structure construction in river basins: floodwater control with secondary levees 3.Adaptation measures for climate change Floodwater control with secondary levees to prevent expansion of a damaged area Yoshida Riv. Flow from break Inundation due to the Aug flood Naruse river Lifesaving from helicopter Yoshida river R flooding T o h o k u R a i lwa y Residential area Dyke break p o i n t flooding Due to 4 break points, 3,060ha was flooded, 1,510 houses were flooded above the floor level, and some parts of the area stayed under water up to 12 days. Naruse river flooding After completion In-service leg of R346 s bypass Expected effect of secondary levee Yoshida river Secondary levee Tohoku RailwayMitigating flood damage at city center Actual flooded area in Aug This secondary levee is under construction in coordination with road construction. flooding

18 A new concept for urban development Compact community easier to implement flood control measures 3.Adaptation measures for climate change Compactly-built residences provide better energy efficiency and easier environment for flood control projects Conceptual figure of compact city for present small and medium cities in Tohoku region Present city Future picture Disorderly-spread city Toward sustainable cities Social sustainability Environmental sustainability Economic sustainability Principles Safe, secure, & comfortable city Attractive & lively city Artistic city with full of history, cultures and nature Sound city with collaboration & participation Concept Compact city in harmony with nature Directions Guarantee safe, secure & prosperous livelihood Provide convenient transportation services Revive the city center and reallocate public facilities Maintain and conserve local communities Curb city expansion & maintain/conserve green agricultural areas Promote artistic & environmentally-friendly community development Provide efficient & effective public services Source: Committee on compact city in Tohoku region Compact city harmoniously surrounded by nature Green and Agricultural area with residences Urban area where people can reside and make a living Oya River Houses relocated to this area Urban center Suburb area where people can enjoy affluent life Suburb Pond Green area Source: Committee on compact city in Tohoku region Urban center Suburb Green area Forest Agri field Rural Settlement Kokai River Hakojima retarding basin (constructed in 1990)

19 Adaptation measures in step with local community development 3.Adaptation measures for for climate change 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 2 disaster hazard area Class 4 disaster hazard area Example of Nagoya city Class 3 disaster hazard area Class 1 disaster hazard area Sample ordinance restrictions (Nagoya City) Adopting pilotis to prevent damage to buildings during a flood

20 Adaptation measures with emphasis on crisis management 3.Adaptation 6. Japan's measures response to for climate change Building of a wide-area disaster prevention network that connects embankments, roads on the dry river bed for emergency traffic and elevated roads to wide-area disaster prevention bases. Reinforcement of actions in the initial stages of a disaster for minimizing damage and restoring infrastructure early, and enhancement of an organizational setup to achieve the goal Technical Emergency Control Force (TEC-FORCE) TEC-FORCE Organizational setup Staff of Regional Development Bureaus and Offices Field support center Engineers of National Institute for Land and Infrastructure Management and Public Works Research Wide-area infrastructure force Institute (rivers, roads, sediment control, ports, etc.) Technical support group (engineers) Sewerage system force Building land force Buildings force Private sector construction organizations Contract/ agreement (operators of equipment) Coordination Staff of local public entities Network of roads and river embankments Inundation of Route 34 during a flood in July 1990 Image of road-embankment connection Activities -Investigation of damage -Quick repairing -Prediction of degree of damage risk -Planning of control measures -High-level technical guidance -Assistance in reconstruction Drainage pumping vehicle Disaster control helicopter

21 Adaptation measures with emphasis on Preparedness 3.Adaptation 6. Japan's measures response to for climate change Share preliminary information concerning the degree of flood risk Water levels in built-up areas in the past floods are indicated on the hazard map. Information dissemination channel Flood hazard map of xx City 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) Hints on escape and necessities Potential inundation areas and depths of inundation Image of a flood hazard map Easily recognizable signs

22 Adaptation measures with emphasis on Preparedness Share real-time information 3.Adaptation 6. Japan's measures response to for climate change 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 Gauging station Gauging station Information provision via cellular phone or personal computer Delivery of an image to a TV screen Flood alarm office Surveillance camera River office Flood (water level) prediction system Meteorological observatory Floodwater prediction through real-time simulation

23 Adaptation measures by Advanced Technology Utilization of Aerial Laser Survey Aerial Laser Survey is a surveying technology of three-dimensional digital terrain data. For surveying, laser pulse are radiated from aviation, and analysis of reflected laser pulse from ground surface. Terrain data such as figure of cross section of flood prone area can be obtained by this survey. Advantage point Preciseness Elaboration of inundation analysis More elaborate inundation area can be obtained by detailed terrain data such as roads, railways and embankments. Identification of effective countermeasures about inundation, such as prevention inflow to underground arcade by accuracy inundation height Swiftness Quick investigation on natural disaster damage GPS Satellite GPS Ground Station Specification Accuracy Standard Deviation 25cm Depend on Equipment, height 3.Adaptation measures for climate change Laser Digital image (Optec 3100DC, AGL2000m)

24 Adaptation measures by Advanced Technology Aerial Laser Survey Utilization for Adaptation measures 3.Adaptation measures for climate change

25 (C.f.) Earthquake damage investigation by using Aerial Laser Survey Landslide dams Lake were built in several places by the Iwate-Miyagi Nairiku Earthquake in Aerial Laser Survey Data was used for consideration on finding appropriate countermeasures. Aerial Laser Survey can be useful in the case of difficult situation to approach the damage area. Understanding of landslide dams lake by three-dimensional digital terrain data Measuring deformation volume compared with before-and-after on earthquake Change of height (m) Level (m) 2006 measured 2008 measured

26 Conclusion Prioritized investment to disaster prevention Investment prioritize areas related to disaster prevention for limitation of available capacity Clarification of priority and Planning of road map Drawing up short-term, middle-term, long-term policy by [selection and concentration] as meaning of clarification of prioritized policy. Planning the road map by assessment of disaster risk every term. Adoption adaptive approach Adopting adaptive approach of revising road map in response to future observation and cumulative knowledge New technical development and contribution to the world Contributing to the world by transferring of new technology and Japanese expertise, policy, technology Participatory approach Participatory approach is necessity. Informing to be understood easily to citizens. Adaptive Approach Revising adaptation measures by analysis of water-related disaster risks with improvement of flood prediction by monitoring changes of climate change and social condition. Flood Risk Drawing up Adaptation measures Monitoring Monitoring Monitoring Monitoring Range of prediction Revising Revising Adaptation Adaptation measures measures Prediction by climate change Reduction risks by adaptation Accuracy enhancement Range of prediction Range of prediction Revising Adaptation measures Past Now Future