Flood Management in

1. Comprehensive Flood Control Measures 2. Provision of River information 3. Responses to the Niigata Torrential Rain Disaster 4. About ICHARM 5. Responses to 2011 Thailand Floods 6. Outline of the Tsunami-Resilient City

19 Issues in Past Disasters

(1) Near small and medium-sized rivers with relatively small catchment area, when localized torrential rain occurs frequently, adequate steps were not taken for evacuation of residents due to the poor information provision structure. A junior high school cut off by flood waters (2) The elderly, small children and others needing Overflowing of smaller rivers (Ikarashi (July 2004 Niigata-Fukushima assistance in a disaster were frequent victims, River) (July 2004 Niigata-Fukushima Flood Disaster) shihowing pro blems w iththith the warn ing an d evacua tion Flood Disaster) SKdNSource: Kyodo News system. (3) Evacuation orders, etc. were slow in coming or were ignored by many residents, indicating the need for greater awareness of disaster information on both issuing and receiving ends. Bus stranded on highway (4) With more people using subways and after flooding along Yura River (Typhoon Tokage, Oct. 2004) underground shopping areas , etc., which frequently Source: Yomiuri Shimbun become inundated, the need arose for flood Residents who were slow to evacuate being rescued by SDF prevention measures and effective evacuation (Sept. 2000 Tokai Flood Disaster) systems.

In ligg,ht of these issues, the Flood Control Act was revised twice, in June Flooded underground Hakata subway flooding 2001 and May 2005. passageway (Fukuoka flood of July 2003) (Sept. 2000 Tokai Flood Disaster) 20 Elaboration of Information Dissemination during Floods The Governors of each prefecture shall conduct forecasting of floods in rivers with large scale catchments except those designated by the Minister of MLIT which are vulnerable to large scale of flood damage (Article 11 of “Flood Fighting Act”). Before Amendment After Amendment The Minister of MLIT designates the In addition to the Minster of MLIT, the rivers, which likely bring about Governors of Prefectures newly designate serious damage by floods to the rivers, which likely bring about serious people’ s livelihood, and conduct damage by floods and conduct flood flood forecasting. forecasting. As for the major rivers except those in which flood forecasting is to be conducted, the water leve ls for s tarti ng evacua tion s ha ll be dec ide d an d the r ivers concerne d s ha ll be des igna te d. Before Amendment After Amendment ・In the rivers havinggg a large In the major medium and small sized river, the catchment area, flood forecasting information that the water level has been shall be conducted. reached to the concerned level for evacuation shall be provided. ・As the medium and small -sized rivers in which flood forecasting is difficult, essential water level information for evacuation has not been provided before. 21 Designation and publication of flood inundation areas Based of the article 14 of the flood-fighting Act, river administrators (MLIT and prefectural governments) designate areas that may be inundated in the event of flooding as flood inundation areas.

22 Preparation and dissemination of flood hazard maps Based on the article 15 of the flood-fighting Act, municipalities prepare and disseminate flood hazard maps to residents on the basis of flood inundation area maps.

Information transmission routs Names, locations of evacuation sites

Contact information (government offices, hospitals, public utilities) Location of underground facilities

Designated flood Tips, things to bring inundation area and expected depth when evacuating 23 Forecasting Flooding by Large Rivers With regar d t o w at erw ays r unnin g thr ough tw o or m or e pr ef ect ur e di stri ct s, th e Mini st er of L an d, Infrastructure and Transport must indicate the water level or flow rate after flooding, or the areas to be inundated after overflow and the depth, and must notify the situation to the local governors as well as to the general public with the cooperation of news media as necessary. (Ar tic le 10 (2) o f Floo d Con tro l Ac t)

Before Flooding of Tone Basin by Typhoon Kathleen (Sept. 1947) Levee Breach at Higashi-mura Flood forecasting based only on river Breach points water level and flow rate. (breached 12:25 a.m. on 16th)

16th After revision

In addition to conventional flood 17th forecasting data, also forecast the areas to be inundated after overflow and the depth so that residents can be evacuated properly. 18th

Notation *The waterways and districts are selected for 19th forecasts of inundation levels considering the : Depth less than 50cm population and assets inside the area and the : Depth 50 cm to 2m time flood waters are expected to reach the area. : Depth 2m or more 20th 24 Issuing Flood Forecasts (example for ) In floods, actual and forecast rainfall, water levels and other data are used to calculate inundation in real time, and the areas and depth of flooding are forecast based on the results.

Flood forecasting steps (guidelines) Reference figure for flooding forecast announcement: Progression of flooding (1) Collect and exchange data (2) Forecast flooding Gunma Prefecture (3) Forecast flood levels

Flooding analysis system (upstream Tone River) Tochigi Prefecture

Breach point: Tone River right bank , 136km ○× Date, time of breach

Date, time, expected scope

×: Time of breach

Date, time, expected scope RdRandom po itints × selected Notation Chiba Prefecture : Depth less than 50cm Tokyo : Depth 50cm to 1m : Depth 1m to 2m : Depth 2m to 5m (4) Write up announcement : Depth 5m or more ○× : Breach point (5) Issue forecast : Flooding scope 25 Improvement of Technical Terms for Disaster Management of Floods, etc.

To provide understandable disaster information aiming to lead appropriate judgment and actions by receivers, following improvements are conducted: ・ Setting-up of water levels: To set-up risk level of water levels considering extent of

※To unify the color over the country to recognize the risk level

Risk Rivers designated for flood Action required by local Water level Level forecasting governments and inhabitants Rivers to be known water levels 5 Occurrence of Information of occurrence of Rescue of inhabitants who （ Da inundation inundation in ○○River out slipped for evacuation n gerous 4 ） Critical water level Information of dangers of Completion of evacuation by （ of inundation inundation in ○○River inhabitants A lert ）3 Information of warning of Warning water level inundation in ○○River Issuance of advice for （

C to start evacuation In case that WL has reached the warning water conducting evacuation a level to start evacuation or is anticipated to ution reach up to the Critical Water Level of 2 inundation. ） Pre-cautious water Pre-cautios water level of Issuance of information for level of inundation inundation in ○○River preparation of evacuation 1 Water level for stand-by Stand-by of flood fighting of flood fighting corp. Warning for flood fighting corp. 26 Providing river Provisioninformation of river information Routinely measured river information* is provided in real-time (24hours a day, 365 days a year) to river managers, muniiicipa l superv isors, an d o ther s tttate depar tmen ts. *Includes various data from radar, rainfall measurement stations, river water level meter stations, dams The Ministry of Land, Infrastructure, Transport and Tourism provides river information in real time, 24hours a day, 365 days a year throughout Japan to help protect lives and property from rainfall-induced river and land-based hazards Nationwide data on radar-measured rainfall, Sent to river managers, river water level/flow rate, ground-level Data is collected, processed and edited into an municipalities, state rainfall, dam influx/discharge etc. is easy-to-use form and transmitted depts. etc. via Internet measured and sent by telemetry andllhd cell phone Collection Data is acquired from 17,300 stations nationwide every 10 Transmission Radar rainfall Data is provided to data minutes. each user in an easy- River manager Processing ・ to-use form Editing depending on their Flood River water Collected data is level/flow rate processed and edited needs. into easily understood (information by tables, graphs, maps, time/location diagrams etc. provided as needed) Municipalities Rainfall measurements

Landslides

State depts. Dam influx/discharge 27 Provision of River Information

River inf orm ati on th at ar e pr ovi ded Rainfall/water level/flow volume Indicates relation between water level of the river etc. or standard water level, and level of residential area Radar rainfall Item Planned Maximum water volume Sustainable water level of flood Flood warning Evacuation water Flood hazard Planned high Rainfall Standard fighting corps water level level water level water level dist rib uti on, Level Current rainfall value intensity can Cumulativ Rainfall be viewed in rainfall

time series in e the transition of rain area

Flow volume Flow volume Water level

Warning information Flood warning Water level Flood advisory Indicates flood forecast and Stand-by water level Flood warning water Evacuation water Flood hazard water Planned high flood Ashikaga for flood fighting corps level level level water level prevention warning, etc. List of water level above the standard Lists water level observation stations that indicate a level above the standard, such as flood hazard etc.

Water Time of Standard water level (m) Observation station Water Stand-by for Managemen River name level observatio Location Ora-cho Tatebayashi name system flood Flood Flood Planned t n Evacuation fighting warning hazard high Ashinoko corps Ashinoko Lake Kanto, others Municipality lake National Chiyoda-cho Uji River Left bank Meiwa-cho Mt. Makio river 28 Provision of River information by mobile phone Information provided to mobile phones Information provided on the internet Contents •Precipitaion by hyeto meter •Precipitaion by rader rain gggages •Water level etc.

29 Improvement of information systems for gathering and analyzing ○When a disaster occurs, bases are established to collect information and respond to the disaster. ○It i s necessary to es ta blis h sys tems to ga ther, ana lyze, an d s hare var ious kin ds o f in forma tion suc h as wa ter levels, flow rates, and precipitation.

Response to disaster Images of affected areas sent by helicopters River information system

避難判断水位等の超過状況を一目で把握

Floe rates

Sharing various kinds of information through a large screen Water levels Chronological changes in water levels and flow rates 写真：国土交通省関東地方整備局 30 Water levels and rainfall at the Kobashi Bridge on the Togagawa River, July 28, 2008

• An intense rainstorm hit the Togagawa River basin from 2:30 to 3 p.m. A 10-minute period was particular intense in Nagamine and Tsurukabuto starting at 2:40 p. m. • At the Kobashi water-level station, the water level rose 1.34 meters in 10 minutes between 2:40 and 2:50, almost simultaneously with the downpour • Five people were killed, including 3 children, 11 people rescued, and 41 people evacuated

Rainfall per 10 minutes 10分間雨量 鶴甲雨量TsurukabutoTsurukabuto rainfall rainfall H20.7.28H20.7.28 （mm） １４：５０ Water level水位［m］ (meters) 25 １．０１m 24 1.2 Nishi Omiya Ashiya 1.0

Kobe 20 0.8

Omoterokko river system 0.6 15

0.4 Water rose 1.34 meters 10 10 0.2 Nakaichiriyama rain-gauge in 10 minutes station 0.0 5 Shizennoie 5 １４：４０ rain-gauge station 六甲 -０．３３m -0.2 川 2 2 111 0 -0.4 Tsurukabuto rain- 14:00 14:20 14:40 15:00 15:20 15:40 16:00 杣谷川 gauge station

Rising water levels at the Kobashi bridge (photos from a Kobe monitoring camera)

Nagamine rain- 水位：－０．３３Water level: -0.33 metersm 水位：１．０１Water level: 1.01 metersm gauge station １４：４０ １４：５０

Kobashi bridge a ww River Togaga

From a Hyogo Prefecture report by the First Small and Mid-Sized River Water Damage Prevention Study WG 31 Rainfall Observation in the Past ・ 26 units of C-band radars monitor across Japan as well as the conventional ground rain gauge, for monitoring the rainfall in a wide-area. ・ Although effective for observing frontal heavy rain in a wide-area, detecting sudden intense rainfall in details may be difficult. Radar rain gauge system (located at 26 radar observation stations in Japan) Radars of River Bureau (26 units) Quantitative display of :240km (120km radius)

Radar station Detects rainfall in a wide ide-area Spread Conventional rain gauge system (located at around 9,000 rainfall observation stations in Japan) Rain cloud Direction and velocity

Intensity

Spread of rain area, rainfall intensity are observed every 5 minutes, which enables Ground rain gauge predict direction of transition of rain area Detects rainfall only at the observation point as well as its prosperity and decline 32 X-band multi-parameter rain radar for torrential rain

Existing radar (C-band radar) X-band MP radar - Min. observation area: 1 km mesh - Min observation area: 250 m mesh - Observation interval: 5 minutes - Observation interval: 1 minute - Time to end user: 5 to 10 minutes - Time to end user: 1 to 2 minutes - Obs. Radius: 120 km - Obs. Radius: 60 km

雑司ヶ谷

High 大手町 frequency 世田谷 (5-fold) High resolution (16-fold)

*In contrast to C-band radar (observation radius of 120 km), which is suited for broad-area precipitation observations, with X-band radar (observation radius of 60 km), detailed and real- time observation of local heavy rain is possible though the observable area is small. 33 Characteristics of the X Band MP Radar

1Hih1. High reso ltilution ( (hcharact eri itistic of fXb X band) Radio wave received ・ Wavelength of X band radar is shorter compp,ared to C band radar, and enables Radio wave transmissio Reflectivity factor observation of high resolution. n

2. High real-time performance Radio wave received Horizontal wave (characteristic of MP radar) ・ By transmitting 2 types of polarized Vertical wave waves (()horizontal and vertical), the shape Reflectivit yfactory factor Doppler speed Parameter of of the raindrops are detected, and from polarized wave the ellipticity of the raindrops, the rainfall quantity can be estimated. ・ A highly accurate rainfall observation data can be transmitted almost at real-

time without correction made by the 雨粒形状の変化を把握Detect and analyze transformation of ground rain gauge. raidindrops 3. Wind observation (Doppler function) Radio wave received

・ Win d o bserva tion bithby measuring the Radio wave transmission raindrop speed using the Doppler function. Reflectivity Doppler speed factor 34 Difference between Conventional Radars and X-Band MP Radars [[pComparison between X-band MP radar and existingg] radar]

Radar type C-band radar (existing) X-band radar (new)

Frequency and wavelength 4 to 8 GHz, about 5 centimeters 8 to 12 GHz, about 3 centimeters

• Measure rainfall (narrow area, detailed) Measurement application Measure rainfall (broad area ) • Measure occurrence of rainy area and movement path

Measurement interval Five minutes One minute (target)

Time lag to data Five to 10 minutes One to two minutes (target) announcement

Resolution of provided data 1 kilometer 250 to 500 meters

Doppler measurements Partial Available (wind measurements) (possible at some stations) 3D scan Scan directionality Planar scan (ascertain the raindrop formation process) Dual polarization radar Partial Available (determine state of raindrops) (possible at some stations) 35 Delivery of X-band MP radar（Lanch on 7.2010）

{ Observation information that is acquired based on test operation is delivered as Web images. { The o bservat ion areas for w hihifhich informat ion dlidelivery imp lemente d at t hiihis time are t he 4 areas o fKf Kanto ChbChubu, KikiKinki and Hokuriku. { 2 types—current rainfall images (updated every minute) and historical images (from 30 minutes beforehand to current state). { Delivery of observation information is carried out through the following URL . http://www. river. go. jp/xbandradar/ [X-band MP radar delivery image (Nationwide version)] [X-band MP radar delivery image (Detailed map)]

Select from 4 regions History display button

Specify scope of enlargement When History is selected, it is possible to [X-band MP radar delivery image (Wide-area map)] display videos from 30 minutes ago 36 Actual Observation Samples with X-Band MP Radar (Heavy Rain in Itabashi on July 5, 2010)

[Broad-area map] Enlarged maps

埼玉県 19:00 Itabashi City 19:10 Hall Rainfall legend 千葉県

Tokyo東京都

No data 神奈川県

19:20 19:30 19:40 Shakujii 19:50 River

20:00 20:10 20:20 20:30

37 Actual Observation Samples with X-Band MP Radar (17:00 to 21:30)

H22.7.5 17:00～21:30

Itabashi City Hall

Rainfall legend

No data 38 Comparison with rain gauge (Tokyo, July 5, 2010)

Itabashi, X band MP radar provides Tokyo accurate and quasi-realtime rain data without rain gauge calibration.

地点：板橋（自治体）Itabashi 30

地上雨量(mm)Rain gauge (mm) 25 Xバンドレーダ雨量(mm) X band MP radar (mm)

(mm) 20

15 0分間雨量 in rainfall 11 10 mm 10- 5

0 17:00 17:40 18:20 19:00 19:40 20:20 21:00 21:40 22:20 23:00 2010年7月5日 39 Terrestrial Digital Broadcasting in Kyushu Region (July 20, 2010)

Approximately 4 to 6 screens created for each prefecture. Screens can be switched arbitrarily using a remote control.

For rainfall, the four shades as The squares on the map are water level observation locations. represented by the circles express the For selected observation locations, the color flashes. intensity of rain, and the maximum number Information for the selected observation location (changes in of observation locations is 9 locations. water level), and the current level, etc. are displayed. 40