Overview of Flood Warning System and the role of NMHS in Japan

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1 Overview of Flood Warning System and the role of NMHS in Japan Akira TERAKAWA Deputy Director of ICHARM Public Works Research Institute (PWRI) Tsukuba, Japan

2 I am going to talk about Background - Importance of Flood EWS for integrated flood risk management Role of NMHS in Flood EWS Integrated River Information System for sharing data Challenges for the future step

3 Various Natural Disasters over the World From World Atlas Ninomiya Shoten, 23

4 Geographic Conditions of Japan 7% of land is covered with forests and mostly mountaneous 5% of popuration and 75% of assets are concentrated in flood plains (1% of land) Heavy rainfall occur during rainy season in June-July and in the typhoon season in August- October Rivers are short and steep, causing sharp hydrograph The ratio of maximum/minimum discharge is extremely high (about 1 for Tone River)

5 Inhabitable area / National land area England Netherland USA France Germany Japan (Prepared by MLIT) (%)

6 Population in flood plain / Total population (%) England France USA Germany Japan Netherland (Prepared by MLIT)

7 Fukuoka Flood in 1999 (Source : MLIT)

8 (Source : MLIT) Tokai Flood in 2 (Dyke Break of the Shinkawa river 12 th Sep. in Nishibiwajima town)

9 Inundated situation of Sanjo City, Niigata Prefecture after downpour in July mm/day of rainfall was recorded at Tochio Observatory. (Source : MLIT)

10 Intensive rainfall events are in increasing trend 1. Number of events of 5 mm or more rainfall per hour 5 (instances/year) ~ ~ ~ Average events Average 29 events Average 234 events Number of events of 1 mm or more rainfall per hour 1 (instances/year) ~ Average events Annual total of hourly rainfall events (Source: approx. 1,3 AMeDAS locations across Japan) 1986~ Average events 4.7 Average events 1996~25 Average

11 Amendment of the River Law (River Bureau, MLIT) Introduction of integrated river system management Enhancement of water-use regulations Improvement and conservation of river environment Introduction of plans reflecting public opinions

12 Proactive Mitigation Flood hazard map Flood forecasting/warning Flood insurance Disaster prevention drill Water proofing of buildings Reactive Emergency Response Flood fighting Information sharing Evacuation order Rescue operation Evacuation camp Prevention River improvement Strengthening of levee Storage facility Land use regulation embankment Recovery Recovery operation Prevention of epidemics Reconstruction of buildings Investigation of cause Drawing lessons Integrated risk management considering the total balance of proactive and reactive measures is important

13 River administrator and Meteorological agency jointly issue flood forecasting Rainfall data from radars Rainfall and water level gauging Meteorological information Joint announcement Ministry of Land, Infrastructure, Transport and Tourism Prefectural governments Flood (water level) forecasting Flood forecast Meteorological Agency Weather forecasting Municipal governments Mass communication media Evacuation recommendation Residents

14 Risk levels of flood warning Example of Flood Forecasts Levee

15 合計地下水位海象気象排水機場堰ダム水質取水水位積雪流域平均雨量雨量合計他所管水資源機構国土地理院海上保安庁気象庁道路局都道府県河川局合計地下水位海象気象排水機場堰ダム水質取水水位積雪流域平均雨量雨量合計他所管水資源機構国土地理院海上保安庁気象庁道路局都道府県河川局 (source MLIT : as of March 27) Number of telemetry stations Japan Meteorological Agency River Bureau Municipality Road Bureau Maritime Safety Agency Geographical Survey Institute Japan Water Agency Other organization Total Rainfall amount Mean rainfall amount in the basin Snow cover Water level Water intake Water quality Dam Weir Pump station Weather Oceanographic conditions Groundwater level Total

16 Radar Raingauges Network Radar rain gauges have been installed at 26 locations throughout the country. The information of 1-km mesh resolution is updated every half an hour and available on the Internet. The radar data are calibrated on line using the ground data (1-min. telemetered data).

17 CCTV monitoring network Ministry of Land, Infrastructure, Transport and Tourism Regional Development Bureaus and River Offices have real-time access to 3,9 CCTV images available on IP (Internet protocol) network. CCTV images are used for developing disaster control plans. Number of CCTV sets installed Number as of March, 27 Road River Sabo Other Total Hokkaido 1, ,892 Tohoku ,551 Kanto 1,153 1, ,512 Hokuriku ,259 Chubu ,789 Kinki ,564 Chugoku ,495 Shikoku ,26 Kyushu 742 1, ,948 Okinawa Sample dynamic image (Yodo River in Osaka on August 14, 27) Total 7,466 6, ,132 As of October 26

18 Integrated River Information System Through data transmission among HQs, Regional Development Bureaus, and Offices, nation-wide real time river data can be obtained in an integrated manner. Headquarter s Regional Development Bureaus Offices

19 River disaster prevention information (internet( internet-based) Information to be provided Radar rain gauge data Telemetry data (water levels, rainfall amounts, etc.) Flood forecasting and warning Dam-related parameters (notice of release of water from the reservoir, reservoir water storage, etc.) Water 河川の水位 level graph "river disaster prevention information" website 雨量観測グラフ Hyetograph

20 River disaster prevention information Mobile Top Menu (mobile phone-based based) The system is designed for all user categories (river administrators, local governments and the general public), with information access features and content tailored to each level.

21 Flood Hazard map prepared by a municipality

22 Recent severe flood disasters in Japan Flood in Hyogo Pref Flood in Aichi Pref. Water level rapidly rose by 134cm in 1 min. largest-ever rainfall per hour 雨量 Amount Amount rainfall rainfall per per hour hour Cyunichi New Paper mm/h Cyunichi New Paper Break Point

23 Short-period rainfall forecast by JMA Short-Period Rain Prediction is issued every 3 minutes to provide forecasts of one-hour precipitation for the next 6 hours with 1-km spatial resolution. Not only changes in rain distribution, but also geographical factors and numeric estimates are taken into considerations. 1 hour 2 hours 3 hours 4 hours 5 hours 6 hours

24 Monitoring local storms using X-band MP radars Meteorological radars (X-band MP radar) of a high resolution will be established in the three metropolitan areas, etc. where local storms can cause serious flood damages and will be used combined with the network of 26 C-band radars to enhance monitoring of local storms. A flood prediction method will be quickly developed jointly with related organizations to also predict development and moves of local storms. Advanced use of X-band radars High-frequency and high-resolution monitoring of rainfall distribution Monitoring the development of clouds and winds in the skies by volume scanning Combining with data from C-band radars on rainfall distribution and numerical forecast in large areas X-band radar Existing radar rain gauge (C-band) C-band radar Predicting local storms in 1 to 6 minutes (predicting development of cumulonimbus clouds that bring storms) High-frequency and highresolution monitoring of the target area Monitoring a large area Dual polarization radar (X-band) Dual polarization radar (X-band) Rainfall monitoring to cover the gaps of existing radars in terms of space and time

25 Upgrading and expanding information dissemination to support evacuation Transmitting via digital terrestrial broadcasting Flood Forecast Center (tentative name) Alarm mail ))) Transmitting via 1 seg broadcasting ((( )) The Ministry of Land, Infrastructure, Transport and Tourism will open a flood forecast center in 29 and will increase both the means of communication and the kinds of information for supporting proper evacuation. Standards can be set for each person. ((( )) ) Distributing emergency alarm mail

26 Summary JMA, in charge of weather forecasting, and River Bureau, in charge of flood management, jointly issue flood forecasting message, which is the base of evacuation recommendation (order) by responsible municipal government. Various data related to river management are collected and stored in the integrated river information system and shared with stakeholders through internet and cell phone network. One of the challenges for the next step is how to cope with areally and temporally concentrated local downpour, for which X band radar is expected to be an effective tool.

27 END Thank you for your attention

Best Practice of Flood Hazard Map in Japan

Best Practice of Flood Hazard Map in Japan 1. Hazard map in Japan There are about 1,500 municipalities in Japan, which need to prepare flood hazard map. 510 municipalities have already made and disclosed