Contents

国総研ニューズレター

N I L I M N e w s L et t e r■ Outline of and Technical Support for the Large-scale Sediment Disaster Triggeredin the Kii Mountains by Typhoon 12■ Study Tour and Observation to Modernize the Facilities of the RDCRB,Indonesia■ Development of a Method for Evaluating Energy
Saving Renovations of Detached Houses and Apartments(2010-2012)

No.38■ Application of HF-radar System to Improve Tsunami
Alert Systems and Reduce Tsunami Hazards

Autumn 2011
Outline of and Technical Support for theLarge-scale Sediment Disaster Triggered inthe Kii Mountains by Typhoon 12Erosion and Sediment Control Division,
Research Center for Disaster Risk Management

This article reports on the response by the National Institutefor Land and Infrastructure Management (NILIM) to sedimentdisasters caused by Typhoon 12: its emergency inspection of thedamage and its technical support.
Typhoon 12 of September 2011 caused a total of 100 sedimentdisasters in the three prefectures of Nara, Wakayama, and Mie, resulting
in severe losses including 56 people dead or missing (Ministry of Land,Infrastructure, Transport and Tourism (MLIT), Erosion and SedimentControl Department (Sabo Department), as of October 26). In the same
region, the Totsukawa River disaster of 1889 and the Aridagawa River
Disaster of 1953 caused many deep-catastrophic landslides, and theregion appears to be particularly prone to such disasters according to the“Deep-catastrophic Landslide Estimation Frequency Map,” released by
the MLIT, Sabo Department and the Public Works Research Institute(PWRI). The recent typhoon caused many deep-catastrophic landslides,
blocking river courses (forming natural dams) at 17 locations (Photo1). The following is a report on the results of emergency inspections
performed immediately after the typhoon.

conducting inspections to prepare for restoration, monitoring andobservation, and evacuation systems.
In cases where conditions stipulated under the revised Sedimentrelated Disasters Prevention Law enacted on May 1 of this year, theform of river course blockage, confirmation of ash fall accompanying a
volcanic eruption, and so on, were satisfied, the regional development
bureau conducted emergency inspections and issued emergency
reports on the sediment disasters. Following typhoon 12, emergency
inspections based on the same law were conducted for the first time todeal with the blockage of river courses.
An emergency inspection was started by the Kinki Regional
Development Bureau on September 6 based on the results of theinspection by TEC-FORCE, with technical support from the NILIM
and PWRI. The emergency inspection included measuring theassumed start points of overflows, the relative heights of the naturaldams, the lengths of submerged ground, etc. using a portable laser
range finder from a helicopter and GPS, clarifying the form of eachnatural dam. Based on the results, regions at risk of disasters caused
by debris flows, etc. triggered by the overflow and collapse of anatural dam, and the estimated time of such disaster, were analyzed,
and this emergency sediment disaster information was shared withlocal government bodies on September 8, two days after the startof the inspection (Fig. 1). Based on this information, each local
government body issued evacuation orders on the same day so that
residents could be properly evacuated.
Land at risk of damage by debris flows, etc. triggered by a breach of thenatural dam
District name: Drainage basin of the Kumano River (Totsukawa River)
Akatani, Otocho, Gojo City
Layout of the maps
The predicted inundated ground is displayed
divided into a number of maps as shown below.

LegendLand at risk of damage by debrisflows
Land predicted to be inundated

Photo 1. Blockage of River Courses by Typhoon 12(Iya, Tanabe City, Wakayama Prefecture)

The MLIT dispatched TEC-FORCE (Technical EmergencyControl Force) consisting of erosion and sediment control experts(staff of the Erosion and Sediment Control Division) to the threeprefectures from September 4 to 6 to inspect the state of the disaster(by helicopter and ground inspection) and provide technical support
for recovery. (1) In Mie Prefecture, no river courses were blocked,
but many debris flows occurred in Kihocho Town, Kumano City,and Owase City. (2) In Nara Prefecture, a large collapse several
hundred meters in length and width occurred, starting near a ridge
line in the Totsukawa River Basin, blocking river courses, and inother cases, a river was temporarily blocked until overflow erosion
allowed the river to flow again. (3) In Wakayama Prefecture, alarge-scale river blockage occurred in Iya, Tanabe City (Photo 1),and large-scale collapses were found at several other locations. Inthe Nachigawa River Basin, debris flowed down many tributaries
on the left and right banks of the main river course.
In all three prefectures, sediment produced and discharged bycollapses and debris flows, etc. remained on the mountainsides andtorrent beds, so the TEC-FORCE gave advice on precautions whenGojo City

【留意事項】
この図は、熊野川（十津川）流域五條市大塔町赤谷において、台風 12 号の豪雨により大規模な河道閉塞が形成され、上流に湛水が発生しており、今後、土石流の発生が想定されることから、平成 23 年 9 月 5 日〜 7 日に実施したヘリコプターによる上空からの河道において堆積した土石等の高さ等の調査結果を踏まえ、河道閉塞部における越流によって発生する土石流により被害が生じるおそれのある区域を、以下の条件のもとで数値氾濫シミュレーションにより明らかにしたものです。
○数値氾濫シミュレーションの前提条件
土石流の誘因となる水条件：河道閉塞の上流の湛水が、堆積した土石等を越流し、浸食しながら流出する水量
氾濫範囲設定条件：粒径 1cm 以上の土石が水と一体となって到達しうる範囲○数値氾濫シミュレーションの精度管理上の注意点
数値氾濫シミュレーションでは、概ね 50m 間隔の標高データで氾濫域の地盤高を表しており、砂防設備、橋梁、築堤、水路等の地物の形状が正確に再現されていない場合があります。
河道閉塞を形成している土塊の形状は上空から簡易に計測した結果に基づき、数値氾濫シミュレーションを実施しております。また、堆積した土石等の土質調査等は実施していないため、土石の粒径等を想定して数値氾濫シミュレーションを実施しております。そのため、実際の土石流現象が正確に再現されていない場合があります。
他の河川との合流による河川水の増加は考慮していないため、洪水中に土石流となって氾濫が発生した場合には、表示より広い範囲に土石流の氾濫が及ぶおそれがあります。

Totsukawa Village

Figure 1. Example of an Emergency Sediment Disaster Inspection ina District at Risk of Disaster by a Debris Flow Triggered by Inundation,
Overflow and Collapse of a Natural Dam1

Study Tour and Observation to Modernize
the Facilities of the RDCRB, Indonesia
International Research and Promotion Division,
Planning and Research Administration Department

From September 26 to 30, 2011, the NILIM held a study tour
for the Research and Development Center of Roads and Bridges(RDCRB) of the Ministry of Public Works of Indonesia.
This study tour, which was planned and held in preparation formodernizing the facilities used to test bridges and structures at theRDCRB, included visits to related research institutes—the Public
Works Research Institute, the Building Research Institute, and thePort and Airport Research Institute—and also a tour of the ThreeDimensional Full-Scale Earthquake Testing Facility (E-Defense)at the National Research Institute for Earth Science and Disaster
Prevention. With the cooperation of the Honshu-Shikoku Bridge
Expressway Co., Ltd. and the Hanshin Expressway Co., Ltd., theparticipants also observed road management and bridge structures(Akashi Kaikyo Bridge and Minato Bridge) and visited a memorial
library to learn about the materials and structures damaged by
the Hanshin-Awaji Earthquake in 1995, including temporary
countermeasures during the emergency. This tour in the Kansai
Region was impressive and educational for all members in theirspeciality. We are confident that the study tour has helped strengthen
the research bonds between our research institutes.
(Future schedule)
Japan and Indonesia are both prone to earthquakes and othernatural disasters, and intend to deepen their mutual cooperation inthis field in order to protect their own economies and people. Ata meeting of representatives of the two research institutes on theday the Indonesian delegates arrived, Director-General Kazuhiro
Nishikawa and Director-General Jawali Marbun confirmed thatDevelopment of a Method for Evaluating Energy
Saving Renovations of Detached Houses andApartments (2010-2012)
Residential Environment Planning Division, Housing Department

To promote energy-saving renovations in existing houses, wehave clarified various available energy conservation renovation
methods, and developed an evaluation method to predict theresulting energy conservation rate.
There is an urgent need for society to reduce energy consumption
in houses. So measures to evaluate energy conservation by newly

the Fifth Joint Workshop (including a seminar) would be held inIndonesia next month at the end of October. The workshop will
include research according to the roadmap of joint research themes
confirmed by the Third and Fourth Workshops (http://www.nilim.
go.jp/english/coop/indonesia-4thws-20110603.pdf).

Photo: View of the Study Tour(Top left: Courtesy call to Vice Minister Sato; upper right, courtesy visit toDirector General Nishikawa; middle and bottom: Views of facility tours)

NILIM website (International Activities)(http://www.nilim.go.jp/english/coop/conference.htm)

built houses, Top Runner Standards for Housing Note 1), etc. havebeen introduced. However, there are far more existing houses than
new houses being built, and thus for the entire nation to conserve
energy in houses, it is essential to encourage renovations to improvethe energy efficiency of the stock of existing houses.
Therefore, in 2010, the NILIM began a research project on
improving energy conservation in existing houses Note 2), and thestudy is now in its second year.
Last year, cases of renovation for energy conservation weresurveyed to compile suitable methods such as sun shading,insulating, and replacing equipment and appliances, etc. Renovation

Examples of energy conservation renovation methods (from left, blocking air flow in walls, adding insulation below the floor, sash window attachment method)2

only for energy conservation is rarely done, but is usually combinedwith other work not related to conserving energy (refurbishingthe interior finishing, repairing the plumbing, placing waterproof
materials in bathrooms, etc.). Before such renovations are carriedout, it is necessary to decide how the energy conservation renovation
methods surveyed will be combined and executed.
This year, a method of calculating the energy-saving effects ofthese energy-saving renovation technologies was developed. If thismethod can be applied, it will be possible to generally predict by how
much energy-saving renovations will reduce energy consumption.

For the achievements and progress of this research, please visit:
http://www.nilim.go.jp/lab/icg/shouenekaishuu/
Note 1: Notification No. 2 of the Ministry of Economy, Trade and Industry
and the Ministry of Land, Infrastructure, Transport and Tourism of2009, Top Runner Standard for Housing
Note 2: Development of Energy Consumption Performance Evaluation
Methods for Various Types of Houses (2010 to 2012)

Application of HF-radar System to Improve
Tsunami Alert Systems and Reduce
Tsunami Hazards

These observations suggest that in regions facing a sufficiently broad
continental shelf, it is possible to detect tsunami early on using HF
radar. However, the continental shelf on the south coast of Japan isgenerally only 20 km wide or less. The current velocity induced by
the tsunami off the continental shelf is of the order of the velocity
resolution of the radar or even smaller. To achieve early tsunami
detection using HF radar, further technological development isnecessary.
However, our observations show that HF radar has anotherimportant role, which is to measure the detailed resonance modein coastal regions, since it is important to clarify the mode inadvance in order to take tsunami countermeasures. Basically, mode
calculations for coastal regions with complex topography rely on
a numerical model, but verification has been done based on datafrom sparsely distributed water level gauges in coastal regions.
Therefore, we considered extracting the resonance mode from theHF radar observations and using it to verify the numerical model.
This will allow us to improve the predictions of wave height after
the second wave.
Although tsunamis are rare events, resonance in coastal regions
can be caused not only by tsunami, but also by meteorologicaldisturbances. When typhoons (Nos. 6 and 12) approached the Kii
Channel this year, we measured the surface current velocities in theKii Channel by the radars in the tsunami observation mode. We aretrying to understand the mechanism of the resonance mode excitedin the channel based on these HF radar observation data.

Coastal Zone Systems Division, Coastal and Marine Department

Two important roles of the HF-radar system for tsunami
measures are described based on tsunami measurements in the Kii
Channel.

Distance from radar(km)The tsunami caused by the March 11, 2011 Magnitude 9.0
Tohoku-Oki earthquake reached the continental shelf south of
the Kii Channel about 1.5 hours after the earthquake. At 5:00
p.m. on the day of the earthquake, we switched the observation
mode of HF radars at two sites located on the eastern coast of
the Kii Channel (Figure) from normal hourly observation totsunami observation every two minutes. Signals from the tsunami
waves induced by the earthquake and subsequent resonances weredetected as radial velocity variability by the HF radar installed at
the northern site.
The figure shows the time series of radial velocity along thesixth beam. From the first to the third wave with larger velocity
amplitudes, the phases in the distant ranges lead those in the closer
ranges. The phase relationship gradually changed after the third
wave and became out of phase from 20:00 to 23:00 followed by
the establishment of an in-phase relationship throughout the range
from 1.5 to 30 km along the beam due to resonance. We are now
analyzing the radial velocities from the other radar beams toclarify the processes of tsunami propagation and excitation of thesubsequent resonances in the channel.
Research groups in the United States and Germany also detected
the surface current variability induced by the tsunami wave by using
HF radars in coastal regions in Japan, the United States and Chile.

Reference
Hinata et al., Estuarine, Coastal and Shelf Science, doi: 10.1016/
j.ecss.2011.08009, 2011.

1.5
10

Setouchi Inland Sea
Minato Base

20

Hypocenter

30
20

Saikazaki Base10(cm/s)Kii Channel

No. 6 beam

Shikoku

0

Kii Peninsula-10-20
17:00(March 11)

19:00

21:00

(March 12)

23:00

01:00

03:00

Pacific Ocean

05:00

Japan standard time (hour)3Schedule of Principal Events (November 2011 to January 2012)
Scheduled Dates

Event Name

Nov. 19

Open house: Public Works Day (Asahi Office, PWRI)
http://www.nilim.go.jp/lab/bbg/event/index.html

Nov. 23

Special Conference on Port and Airport Technologies in Tohoku 2011
http://www.ysk.nilim.go.jp/oshirase/linkpage_1.html

Dec. 1

2011 Conference of the National Institute for Land and Infrastructure Management
http://www.nilim.go.jp/lab/bcg/kisya/journal/20111028.pdf

Dec. 20

National Conference on the Restoration of the Sea: Tokyo Bay SymposiumJan. 31 to Feb. 2

Fourth Road/Traffic Workshop with the Institute of Transport Science and Technology, Ministry of Transport (ITST) of Vietnam

PROJECT RESEARCH REPORT of National Institute for Land and Infrastructure Management(August-October,2011)
No.

Title of Paper

Project Leader

33

Risk management methods of the business continuity for the international air/sea transport

Research Coordinator for Advanced Port
Technology

34

Evaluation Method of Countermeasures with Various Utilities against Infrequent Mega-Risk Type
Coastal Hazards

Director of the Coastal Disaster
Prevention Division

RESEARCH REPORT of National Institute for Land and Infrastructure Management(August-October,2011)No.
46

Title of Paper
Overtopping and Overflow Modeling in Storm Surge with High Waves and Estimation of Storm
Surge Inundation Damage Sensitivity to Global Warming in Japan’s Three Major Bays

Names of Divisions
Port and Harbor Department

TECHNICAL NOTE of National Institute for Land and Infrastructure Management(August-October,2011)
No.

Title of Paper

Names of Divisions

637

Trends in Sabo Project Related Studies and Research (VIII)

Erosion and Sediment Control Division

639

Report of Panel Exhibition for Coastal Ecosystem Restoration (3rd, 4th, 5th and 6th)

Marine Environment Division

640

Report of Tokyo Bay Symposium (7th - 11th: Implementing Stakeholder’s Cooperation)

Marine Environment Division

641

Analysis of Current Sightseeing Boats of Active Conduct, Navigation Situation, User Consideration
and Possibility of Regional Resources

Coastal Zone Systems Division

642

Analysis on World Container Ship Movement and Containerized Cargo Flow (2011)

port Planning Division

643

Study on International Air-Passenger Traffic in East and Southeast Asia

Airport Planning Division

644

Report of the research activities of International Research and Promotion Division in FY 2010.

International Research and Promotion
Division■ Documents issued by the NILIM can be viewed at our web site. (http://www.nilim.go.jp/lab/bcg/siryou/index.htm)■ NILIM research activities and achievements are now available on the web site (http://www.nilim.go.jp/english/annual/annual2011/ar2011e.html), as Annual
Report 2011.

National Institute for Land and Infrastructure Management
Ministry of Land, Infrastructure, Transport and Tourism

No.38

Autumn 2011

Asahi 1, Tsukuba, Ibaraki, 305-0804, Japan(Tachihara) Tachihara 1, Tsukuba, Ibaraki, 305-0802, Japan(Yokosuka) Nagase 3-1-1, Yokosuka, Kanagawa, 239-0826, Japan
TEL:+81-29-864-2754 FAX:+81-29-864-4322
Edited and Published by
http://www.nilim.go.jp/english/eindex.htm
National Institute for Land and Infrastructure Management

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