Building Safer Country by Best Mix of Structural and Non-structural Measures including Integrated River Basin Information Handling

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1 Building Safer Country by Best Mix of Structural and Non-structural Measures including Integrated River Basin Information Handling Water and Disaster Management Bureau, Ministry of Land, Infrastructure, Transport and Tourism January 2012

History of flood control in Tone River basin(400years ago) Up to 15 th Century, Tone River crossed the Kanto Plain from north to south and flew into Tokyo Bay

control measures in upper and middle reaches has changed from flood control allowing inundation to sequential levees confinement After this change, the maximum

2 History of flood control in Tone River basin(400years ago) Up to 15 th Century, Tone River crossed the Kanto Plain from north to south and flew into Tokyo Bay From 1594 to 1654, Tone River was connected to Pacific Ocean by eastward channel Tone River Watarase River Kokai River Kinu River After the flood in 1910, flood control measures in upper and middle reaches has changed from flood control allowing inundation to sequential levees confinement After this change, the maximum discharge in the Tone River Channel has increased, which became the main challenge of flood control in Tone River Basin Tone River Watarase River Kinu River Kokai River 1

History of flood control in Ara River basin (130years ago) Up to the

basin to protect central Tokyo area Geomorphological map in 1880 Retarding

Castle Sakai no Watashi Mitsumata Wakare no Fuchi Mountain, hillock Plateau

3 History of flood control in Ara River basin (130years ago) Up to the beginning of 19 th century, upstream area of Tokyo functioned as retarding basin to protect central Tokyo area Geomorphological map in 1880 Retarding basin Constriction point to protect central Tokyo Dyke Dyke Edo (Tokyo) Castle Sakai no Watashi Mitsumata Wakare no Fuchi Mountain, hillock Plateau Natural levee Mound along river track Alluvial fan Raised bed river Sand dune Retarding basin 2

4 Japanese metropolitan area has developed with flood defense woks yeas 1919 Urbanization progressed due to the improvement of the safety level by the excavation of Ara River Floodway 35years years Former retarding basin area has also been urbanized Excavation of Ara River Floodway 3

5 Number of fatalities 6,000 5,000 4,000 3,000 2,000 1,000 Reduction of flood damages in Japan Area inundated (ha) 350, , , , , ,000 50, Number of fatalities and inundation area have dramatically been reduced in Japan due to continuous investment in and efforts for flood mitigation. Source: Water Disaster Statistics, Ministry of Land, Infrastructure Transport and Tourism 4

Fundamental Flow of River Maintenance In Japan

organizations responsible for river management.

assess conditions and conduct repair works, and

It is important to be aware of the actual state

Use visual and machine observations effectively

Functional deterioration (time/force) Detect

construction, waste dumping and other nuisance)

Alteration of state Repair work Identification of

Emergency repairs, etc After maintenance work

地方整備局河川国道事務所出張所 TEL 0 - - Recovery Detection of

offender After removal Assess the status of

surveys, water level observation, etc and conduct

6 Fundamental Flow of River Maintenance In Japan there are national and regional administrative organizations responsible for river management. They manage river channels and levees/facilities, assess conditions and conduct repair works, and ensure safety of river users. It is important to be aware of the actual state and changes to conditions of rivers. Use visual and machine observations effectively to understand the state of rivers. Functional deterioration (time/force) Detect changes to the state of rivers (illegal construction, waste dumping and other nuisance) and bring them back to the proper state. Alteration of state Repair work Identification of who & what Functional maintenance Damages to lowwater revetment Levee slope failure Deterioration due to aging and floods, etc Emergency repairs, etc After maintenance work ゴミの投棄禁止ゴミを捨てると処罰されます河川法二十万円以下の罰金三ヶ月以下の懲役国土交通省地方整備局河川国道事務所出張所 TEL Recovery Detection of illegal waste dumping Warning/Identification of offender After removal Assess the status of rivers by conducting surveying, water quality surveys, water level observation, etc and conduct appropriate maintenance measures such as weeding. Cross sectional and longitudinal surveying Water quality surveying Flow discharge observation (flood) 5 Weeding of levees 5

7 Structural (Hard) Measures for Flood Mitigation At the great flood, the river water level rises and overflows. A) Keeping down the water level by setting back embankments B) Keeping down the water level by flood control functions of dams and retarding basins It needs sea walls to prevent seawater backflow. Discharge channel (flood bypass) C) Keeping down the water level by dredging D) Keeping down the water level by discharge channels Flood control principles Lowering the water level at floods to maintain safe flow of the river A) Keeping down the water level by setting back embankments (increasing the river width) to increase the river capacity B) Keeping down the water level in the downstream by pooling the overflowing water at dams and retarding basins to decrease the flow volume C) Keeping down the water level by dredging (digging down the river bed) to increase the river capacity (It may needs estuary barrages.) D) Keeping down the water level in the downstream by discharge channels to bypass overflowing water Source: Data from MLIT 6

8 Options in Structural (Hard) Measures for Flood Mitigation Ratio between dams and retarding basins at major rivers of the country 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Ara River (Iwabuchi) Kuma River (Hitoyoshi) Toyo River (Ishida) Chikugo River (Arase) Ibi River (Mangoku) Ota River (Kumura) Yodo River (Hirakata) Tone River (Yattajima) Tenryu River (Kashima) Yoshino River (Iwatsu) Kiso River (Inuyama) Shinano Rive (Ojiya) Kano River (Ohito) Onga River (Hinodebashi) Ratio Ratio ダム遊水池の分担率 of dams or retarding basins Ratio 河道の分担率 of river channels The ratio designated for rivers on respective plans Source: MLIT

9 Outline of Flood Mitigation Measures Descriptions (examples) Responsible entity Preventing inundation Flood control (Relevant facility development) Safe housing Alleviating flood water volume Widening river widths, flood control by dam and retarding basin construction and improvement Regulating and Promoting land development, etc. (Urbanization control areas, hazard maps) Development permissions Permissions for measures for rainfall infiltration barriers River conservation authorities (national, prefectrual) River conservation authorities City planning authorities Prefectural governments, etc. Counter measures against flood For emergencies Daily precautions Flood control Evacuations, rescues, etc. Promoting awareness of local residents Drawing up flood control plans Maintaining proper functions of facilities Quick repair of structures and housing, providing accurate information Fixing scouring and leakages Guiding evacuations of local residents, rescues, supports, etc. Giving the residents sufficient information about evacuation location and routes Giving the residents sufficient information about danger of floods Organizing relevant countermeasures against floods Role sharing and clarified responsibilities Flood control centered on riverbed fluctuations Constructing evacuation shelters River conservation authorities Flood control groups Municipal governments Self-Defense Forces and national governmental authorities for large-scale floods, Municipal governments River conservation authorities National and local governments Designated organizations, etc. River conservation authorities Prefectural and municipal governments 8

10 Sharing of River Information Since 1977: Collection of real-time precipitation and water level data advanced due to the unified specification of telemeter systems prepared by the national government. System for viewing real-time river information was developed at each on-site office. Problems The systems used on-site were developed separately at different offices, thus their software, hardware and operational procedures were all different and inconsistent. Dedicated software was needed to view the information. Therefore the river administrators had to order a system upgrade to the developers even for small changes. Only the river information possessed by the office that developed the system could be browsed. Social background Massive human damage caused by Tokai heavy rainfall in 2000, and the severe damage caused by underground inundation by Fukuoka heavy rainfall in 1999 Importance of provision and sharing of accurate information was recognized Improvement of the information and telecommunications infrastructure due to the advancement of IT technology Launching of Integrated River Information System for sharing river information nationwide in System features The data collected and provided includes not only the river information Ministry of Land, Infrastructure, Transport and Tourism (MLIT), but also the data possessed by Japan Meteorological Agency, the prefectural and city governments and the Road Department of MLIT, etc. Anyone including the public can browse the nationwide river information through the internet The river information can be browsed through the web-based interface, thus not dependent on the system environment. By incorporating a common system throughout Japan, total cost was reduced. 9

11 Provision of River information by internet and mobile phone Information provided on the internet Information provided to mobile phones Contents Precipitation by hyetometer Precipitation by radar rain gages Water level etc. 10

12 Information Provision for Encouraging Evacuation In order to promote smooth evacuation actions reference to water levels for evacuation orders have been established and categorization of water levels based on risk levels have been implemented. Risk level Level 5 Level 4 Level Water Level and Risk Level Flooding occurs Flooding nearly occurs River 3 Evacuation should be decided Level Flood is cautionary Flood fighters act 2 Top of Levee Houses Levee Flood fighters stand by Level 1 Low Flow Channel Flood Channel 11

13 Publication of flood-prone area/ Flood Hazard Map MLIT and the prefectural governments designate, as flood prone areas, those areas that may be inundated in the event of flooding. The municipalities prepare and disseminate flood hazard maps to residents on the basis of flood- prone area maps. Flood Hazard Map Evacuation Route Evacuation Shelter 12

Raising Awareness on Flood Hazard Information

residents to escape safely and smoothly when a

[Flood-related symbols] JIS 規格 ( 案内用図記号 )

signs installed This symbol indicates that the

[Evacuation site (building)] This symbol shows

14 Raising Awareness on Flood Hazard Information on the assumed flood water depth, evacuation sites, etc. is indicated in town in order to allow residents to escape safely and smoothly when a flood occurs. [Flood-related symbols] JIS 規格 ( 案内用図記号 ) Z8210:2006 [Flood] Examples of flood-related signs installed This symbol indicates that the area concerned may be affected by floods. [Evacuation site (building)] This symbol shows a safe building that provides a shelter when a disaster occurs. Information on the assumed flood water depth, evacuation sites, etc. is indicated on electric poles and the walls of public facilities. 現在東京都北区 ( 荒川 ) 兵庫県豊岡市 ( 円山川 ) に設置 13

Provision of Evacuation Information using Mobile Phone Early Warning Area Mail Provides disaster information such as Earthquake Early Warnings issued by the Japan Meteorological Agency and disaster

15 Provision of Evacuation Information using Mobile Phone Early Warning Area Mail Provides disaster information such as Earthquake Early Warnings issued by the Japan Meteorological Agency and disaster and evacuation information issued by national and regional public institutions to subscribers in afflicted areas. Each base station simultaneously transmit mail to all users in the coverage area. Information can be received without the impact of line congestion as it uses cell broadcast service (CBS). Japan Meteorological Agency Earthquake Early Warnings Simultaneously sent to areas with potential risk of disasters A pop-up window appear on the screen. Earthquake Early Warnings and Disaster/Evacuation Information are informed by different ringing tone. Saved in the receive mail box with a special icon. Area Mail Center National and regional public institutions Disaster and evacuation information NTTdocomo HP 14

16 Considerations of Flood Hazards in Land Use Regulations Article 39 of the Building Standards Act, Disaster Hazard Areas Costal disaster-prevention areas in Nagoya To Nagoya Sta. Kanayama Sta. Tokaido Shinkansen Atsuta Sta. Tokaido Main Line Category 3 area Height of floor on 1st floor Category 4 area Nagoya Port Category 2 area Height of floor on 1st floor Height of floor on 1st floor Height of floor on 1st floor * Where schools, hospitals, meeting grounds, public offices, welfare facilities for children, and other public architectures located in areas of Categories 2 4 are concerned, one or more residential spaces will be placed on the architecture with the floor height of the first floor of N P(+) 2 m or higher, and with the height of N P (+) 3.5 m or higher. 6 15

Reinforcement of Information Provision in Emergency

provides its results for forecasting of inundation

of rainfall and water level of river in case of

浸水深の経時変化 2 時間後 6 時間後 12 時間後決壊地点等の設定決壊地点の設定 Change of

17 Reinforcement of Information Provision in Emergency Installation of a real time simulation system, which provides its results for forecasting of inundation depth and area based on observed data and projection of rainfall and water level of river in case of flooding is on going. 浸水深の経時変化 2 時間後 6 時間後 12 時間後決壊地点等の設定決壊地点の設定 Change of inundation depth at any point 破堤幅破堤敷高破堤敷高の設定 Select an arbitrary point :time of dyke break 16

that provides technical assistance for fast

dispatched on the day of the disaster, 397

vehicle) Survey of disaster affected areas

18 TEC-FORCE Dispatch TEC-FORCE (Technical Emergency Control Force ): Specialist group that provides technical assistance for fast rehabilitation in the affected areas at the time of large scale natural disasters. (consists of MLIT staff) 62 staff were dispatched on the day of the disaster, 397 staff the next day and there were more than 500 staff by three days later. (18,072 person-day as of Sept 14) 18,072 person-day as of Sept 14 Information & communication team (satellite communication vehicle) Survey of disaster affected areas Supporting affected municipalities (technical assistance) Survey of disaster affected rivers Liaison dispatch (local needs survey) Disaster emergency response (emergency flood removal) 17

21,000 buildings were damaged in Niigata prefecture ).

19 Mega Flood Disasters to Be Tackled July 2004 torrential rain caused inundation in large areas, resulting in extensive damages (Fatalities were 15 and approx. 21,000 buildings were damaged in Niigata prefecture ). Inundation caused by Ikarashi River levee failure (Sanjo City, Niigata Prefecture) : Niigata Disaster Management Office (March 23, 2005) 18

20 Importance of Pro-active/ Preventive Measures In July 2011 the Shinano River Basin in Niigata experienced a torrential rainfall of approx. 1,000mm (cumulative rainfall), the largest rainfall in the recorded history. Total rainfall was 1.6times more than that of July 2004 but both damages to buildings and human casualties were reduced dramatically. Total Rainfall 1) Building Damages 2) Number of fatalities or missing 3) 1.6 times 90% reduction 90% reduction )Kasabori rain gauge station 2)2004.7: 7.13 Rainfall and Flood Damage Report in Niigata (March 2006 Niigata Prefecture) : Produced by Niigata Prefecture based on First Niigata and Fukushima Rain Disaster Management Research Committee (Jul. 2011) 3)Shinano River Downstream, Ikarashi River, Kariyata River Disaster Rehabilitation Emergency Project Pamphlet (Shinano Karyu River Office, Niigata Prefecture)

Water Information Portal Site for More Efficient & Sustainable Water Resources Management

Water Information Portal Site for More Efficient & Sustainable Water Resources Management May 5, 2010 Tomoyuki OKADA Deputy Director, River Planning Division, River Bureau Ministry of Land, Infrastructure,