Journal of Natural Disaster Science, Volume 24, Number 1, 2002, pp15-24

Characteristics of Heavy Rainfall and Flood Damage in Aichi Prefecturefrom September 11th to 12th 2000
Haruhiko YAMAMOTO
Faculty of Agriculture, Yamaguchi University
Kiyoshi IWAYA
United Department of Agricultural Science, Graduate School of Tottori University(Received for 4. Apr., 2002)

ABSTRACT
Record heavy rainfall occurred in Aichi Prefecture from September 11 to 12 2000. We collected about 250 samples of precipitation data observed by various organizations, and analyzed the characteristics of the heavy rainfallthat occurred in Aichi Prefecture. The Midori Ward Engineering-Works Office, Nagoya City recorded a daily
precipitation of 499.5mm on September 11th and 147.5mm on the 12th. The total precipitation was 647.0mm. In
the area from Midori Ward, Nagoya City to Agui Town in Chita district, in the NNE to SSW direction and area
6km wide by 20km long, total precipitation exceeded 600mm. Heavy rainfall of more than 80mm in the area running north and south from Moriyama Ward, Nagoya City to Agui Town appeared at 19:00, and strong rainfall
occurred in the surrounding region. Flood damage was severe in 3km north-south and 1km east-west areas
bounded by the Shin River, JR Tokaido, Nagoya Railroad Inuyama , and Johoku lines. In the southwest part of
Ashihara-cho, Nishi Ward where the bank of the Shin River collapsed and in Nishibiwajima Town, flood depth
exceeded 200cm in buildings.

1. INTRODUCTION
The Akisame-front which had been stagnated near Honshu
was activated from September 11 to 12, 2000 (Tokyo District
Meteorological Observatory, 2000). Because of this record heavy
rainfall was recorded from the evening of the 11th through theearly morning of the 12th in the Tokai District (Ushiyama et al.,2000). Water levels of the Shonai, Shin and Tenpaku Rivers
which flow through and around Nagoya City greatly exceeded thesafe level, breaking past water level records. In Aichi Prefecture,
river banks collapsed in 18 places, flooding occurred in 256 places,rain water remained undrained due to prolonged heavy rainfall,
and flood damage occurred in almost all the cities, towns, and villages in the prefecture (Aichi Prefecture, 2000).
In recent years, we have collected precipitation data from rain
gauges installed by various organizations in order to observe heavy
rainfall precipitation that occurs in connection with typhoons andfronts in Japan, and to analyze the time and spatial features of thatrainfall (Yamamoto et al., 1999abc, 2000). We now have collected precipitation data recorded by various organizations in addition
to AMeDAS (Automated Meteorological Date Acquisition
System) data, for the purpose of analyzing in detail the features ofthe extremely heavy rain generated in the Tokai district.
Furthermore, we investigated severe flood damage in
Nishibiwajima Town and Nishi Ward, Nagoya City.
2.

OBSERVATIONS PRECIPITATION

The position of Aichi Prefecture in Japan, the zone with its thecities, towns, and villages, the city names, etc. are shown in Fig. 1.

Aichi Prefecture is located in the center of Japan and faces the
Pacific Ocean to the south. The Nobi Plain spreads over the western part of the prefecture and the Minamialps mountain range overthe northeast. The Kiso River flows into Ise Bay in the west of theprefecture. The Shonai and Shin rivers flow through the Owari
district, and the Yahagi and Toyo rivers through the Mikawa district into Mikawa Bay.
In order to clarify the time and spatial characteristics of thisheavy rainfall, information from organization’s recording precipitation was investigated, and data about this rainfall were collected.
The numbers of rain gauges installed at facilities to record precipitation in Aichi Prefecture are shown in Table 1, and the positionsin Fig. 2. At the Nagoya Local Meteorological Observatory of the
Meteorological Agency, AMeDAS points are installed in 19 places
within the prefecture. The Nagoya Aviation Meteorological
Station is located at the Nagoya airport, and ground weather surveys are carried out there.
In addition to the meteorological observatories of the
Meteorological Agency, the Toyohashi Construction Office thatmanages the Yahagi and the Toyo rivers, and the 1st class rivers
are managed by the Chubu Regional Construction Bureau of the
Ministry of Construction (presently the Ministry of Land,
Infrastructure and Transport Chubu District Maintenance Office).
Precipitation is recorded in 33 places in the basin. Shonai River
Construction Office, which manages the Shonai and Shin rivers
has rain gauges installed in five places in the basin (eight places in
Gifu Prefecture). Moreover, the Nagoya National Highway
Construction Office, which maintains and manages national highways has observatories for precipitation installed in 11 places, e.g.
along national highway No.1. Each office carries out intensive

KEY WORDS: Aichi Prefecture, heavy rainfall, flood damage, Nagoya City, Nishibiwajima Town, typhoon 0014

16

H. YAMAMOTO & K. IWAYA

Fig. 1

Geographical position of Aichi Prefecture in Japan, the zone of cities, towns and villages in Prefecture, andcity names, altitudes (100, 200, 500, 1000m) and river names.

Fig. 2

Positions of rain gauges installed by various organizations to record precipitation in Aichi Prefecture. The
symbols in the figure are the same as in Table 1. The numbers in the figure are the same as in Table 2.

CHARACTERISTICS OF HEAVY RAINFALL AND FLOOD DAMAGE IN AICHI PREFECTURE FROM SEPTEMBER 11TH TO 12TH 2000

management of precipitation data in real time by a telemeter system. Furthermore, the Water Resources Development Public
Corporation has rain gauges installed in four places for the water
management of the Aichi Canal. The River Division of theConstruction Department, Aichi Prefecture observes precipitation
at 50 places in the prefecture for the purpose of basin managementof 2nd class rivers.
Fire departments have a fire-fighting weather survey system
in 58 places within the prefecture, which provide uniquel information about the main meteorological elements. City office and eachengineering-work offices in Nagoya City, rain gauges are installedin 30 places. Observations also are made in other cities, towns,
Table 1.

Numbers of rain gauges installed by various organizations to record precipitation in Aichi Prefecture.

17

and villages. In the Nagoya Management Office (Japan Highway
Public Corporation, Chubu branch), meteorological survey systems
are made on the Tomei Express Way (in six places) which theoffice manages meteorological elements being managed as data at
5 minutes intervals. Central Japan Railway Company (JR Central)
has installed rain gauges at 20 stations for the safety of rail traffic.
As stated in Aichi Prefecture observations of precipitation
made in about 250 places, which number is about 13 times thenumber of AMeDAS observation points. Moreover, precipitationis recorded at the Waterworks Bureau, water purification plants
and purification centers, in order to manage waterworks and sewers. Because, we are not conducting investigations about the existence of installed the rain gauges. The number of precipitation
observation points may be even more in Aichi Prefecture. By collecting precipitation data from the observatories of various organizations, we could analyze local heavy rainfall.
3. CHARACTERISTICS OF HEAVY RAINFALL
3.1 Heavy Rainfall Analysis using AMeDAS data
Local heavy rainfall occurred in Nagoya City and the surrounding region. Changes in the 1-hour, 10-minute, and accumulated precipitations observed in Nagoya (Local MeteorologicalObservatory) and Tokai (Local Meteorological Observing Station)of the Meteorological Agency from September 11 to 12, 2000 are
shown in Fig.3. In Nagoya, weak rainfall began in the predawn of
the 11th reached a maximum 20 mm/h then stopped during themorning. Rainfall began again around noon and increased inFig. 3

Changes in 1-hour and 10-minute precipitation and the accumulated precipitation recorded at the Nagoya(Local Meteorological Observatory) and the Tokai (Local Meteorological Observing Station) facilities of the
Meteorological Agency.

18

H. YAMAMOTO & K. IWAYA

Table 2. Rainfall conditions 12 at observation points at which the total precipitation on September 11 and 12, 2000.

intensity from evening, becoming a record heavy rainfall with a
total precipitation of 566.5mm from 18:00 to early morning of thenext day.
The daily precipitation (September 11: 428.0mm, records
started 1891), the maximum 1-hour precipitation (97.0mm, records
started 1891), and the maximum 24-hour precipitation (534.5mm,records started 1971) in Nagoya were observed the 1st highest
record. The maximum 10-minute precipitation (26.0mm) was the
2nd highest record, furthermore, the maximum 12-hour precipitation from 16:30 to 4:30 of the next day was 460.0mm. This precipitation is equivalent to 30% of the normal yearly precipitation(1,535mm).
In the Tokai (Local Meteorological Observing Station), located in Tokai City adjacent to the southern part of Nagoya City, thedaily precipitation (September 11: 492.0mm), the maximum 1hour precipitation (114.0mm), and the maximum 24-hour precipitation (555.5mm) recorded on the 1st. Furthermore, the maximum
12-hour precipitation from 16:20 to 4:20 of the next day was
497.0mm. Because of this heavy rainfall, at the 19 AMeDAS
observation points in Aichi, nine points (the daily precipitation)and seven points (the 1-hour precipitation) recorded on the 1st.
3.2

Fig. 4

Changes in 1-hour precipitation and the accumulated precipitations recorded from September 11 to 12 at the Midori WardEngineering-Works Office, the Handa Fire Department,
Higashiura branch and Agui Rainfall Observatory.

Analysis of Heavy Rainfall Based on Precipitation Data
Recorded by Various Organizations
As described in Section 2, rain gauges have been installed inabout 250 places in Aichi Prefecture by various organizations.
Using these collected precipitation data, we analyzed the characteristics of the heavy rainfall in Aichi Prefecture.
Rainfall conditions at 12 observation points at which the total
precipitation on September 11th and 12th are shown in Table 2.
Changes in the 1-hour, and accumulated precipitations from
September 11th to 12th recorded at the Midori Ward EngineeringWorks Office, Nagoya City, the Handa Fire Department,
Higashiura Office, and the Agui Rainfall Observatory (Aichi
Prefecture management) are shown in Fig. 4. At the Midori WardEngineering-Works Office, first there was a weak rain peak frompredawn to early morning on the 11th, then heavy rainfall with a 1hour precipitation of 100mm, which continued into the early morning of the 12th. Daily precipitation on the 11th therefore was of499.5mm, on the 12th, 147.5mm, and the total precipitation
647.0mm. The 24-hour precipitation was 607.0mm (from 5:00 on
the 11th to 5:00 on the 12th), and 12-hour precipitation 521.0mm(from 16:00 on the 11th to 4:00 on the 12th).
At the Handa Fire Department, Higashiura Office, about

CHARACTERISTICS OF HEAVY RAINFALL AND FLOOD DAMAGE IN AICHI PREFECTURE FROM SEPTEMBER 11TH TO 12TH 2000

Fig. 5Distribution of total precipitation over the two days, September 11th and the 12th 2000.

Fig. 6 Distributions of 1-hour precipitation every 4 hours intervals from 15:00 on the 11th to 3:00
on the 12th, including 19:00 on the 11th, when there was maximum 1-hour precipitation.

19

20

H. YAMAMOTO & K. IWAYA

Fig. 7

Times of the recorded maximum 1-hour precipitation from the 11th to the 12th.

Table 3. The extent of damage caused by the heavy rainfall in Aichi Prefecture, September 2000.

CHARACTERISTICS OF HEAVY RAINFALL AND FLOOD DAMAGE IN AICHI PREFECTURE FROM SEPTEMBER 11TH TO 12TH 2000

21

Table 4. Main flood damage in Aichi Prefecture since 1959.

Fig. 8Water level of the Shin River recorded at the Mizuba
River Water Level Observatory, precipitation at the
Nishikasugai Western Fire Department and accumulated
precipitation value.

13km south of the Midori Ward Engineering-Works Office, precipitation was a little less than at the latter office, the total precipitation amounting to 622.5mm and the 12-hour precipitation to506.0mm. Furthermore, the Agui rainfall observatory about 7km
southwest of Higashiura had precipitation of 498mm on the 11th,
124mm on the 12th, and a 12-hour precipitation of 514mm. Total
precipitation exceeded 600mm in seven places, and 12-hour precipitation exceeded 500mm in four places, making clear thatrecord heavy rainfall had occurred over a wide area.
The total precipitation distribution for the two days from
September 11th through 12th is shown in Fig. 5. From Midori
Ward, Nagoya City to Agui Town, in the south-southwest direction
from north-northeast, total precipitation exceeded 600mm over alarge area 6km wide and 20km long. Total precipitation wasrecorded 500mmin southern Kasugai City, eastern Nagoya City,
Nishin City, Kariya City, and northern Tokoname City, all in thisarea. As for the very large 50km x 25km area (Kasugai City, western Nagoya City, Seto City, western Toyota City, Chiryu City,
Takahama City, Handa City, and Taketoyo Town extending eastern Komaki City), total precipitation was more than 400mm.
Distributions of 1-hour precipitation recorded every 4 hours

intervals from 15:00 on the 11th to 3:00 on the 12th, including
19:00 are shown in Fig. 6. Precipitation of 20-29.5 mm/h occurredin the western Owari district of western Nagoya City at 15:00 on
the 11th. From the east of the Owari district to central Nagoya
City, and Tokai City, 1-hour precipitation ranged from 1019.5mm. In other areas, it was less than 10mm.
The 1-hour precipitation was more than 100mm at 19:00 infour places: the Tokai Local Meteorological Observation Station(114mm), the Mizuho Engineering-Works Office (100.5mm), andat Narumi (103.5mm) and Shimoshiota (101.5mm). The heavy
rainfall region, which exceeded 80mm/h appeared in the belt areafrom Moriyama Ward, Nagoya City to Agui Town, and strong
rainfall fell in the surrounding region. 1-hour precipitation of
100mm was recorded at the Midori Ward Engineering-Works
Office (100.0mm) at 21:00, and more than 100mm at the Kariya(109.0mm) and the Takahama (102.5mm) fire departments at
22:00. The heavy rainfall region had moved southeast at 23:00,
and the area with more than 80mm/ ranged from Higashiura Town
to Taketoyo Town in eastern Chita peninsula. It moved into the
Toyo River basin at 3:00 on the 12th, and its showed strong rainfall that exceeded 60 mm/h. Moreover, a strong rainfall area
exceeding 40 mm/h again appeared from eastern Komaki City to
Minato Ward, Nagoya City.
The time of the observed maximum 1-hour precipitation isshown in Fig. 7. The maximum value appeared at 17:00 in thecities, towns and villages adjacent to Gifu and Mie Prefectures.
Furthermore, from Seto City abutting eastern Nagoya City to the
Chita peninsula, the maximum 1-hour precipitation occurred
between 20:00 and 22:00. Maximum 1-hour precipitation wasobserved about 1:00 on the 12th in the Yahagi River basin, andabout 2:00 in the area between the Yahagi and Toyo rivers. In the
Toyo River basin, the maximum was recorded between 3:00 and
8:00.
4. FLOOD DAMAGE
4.1 Outline of Flood Damage
The report of the Fire Defense Agency, compiled on October
2, 2000, states that damage by the heavy rainfall that lasted from
September 10th to 12th affected 18 prefectures (Fire Defense
Agency, 2000). That damage resulted in 10 people dead, 97

22

H. YAMAMOTO & K. IWAYA

Fig. 9Distribution of the depth (cm) of flooding of buildings in the area investigated , recorded by the fire department, (◇)
and water level observatory(□) , and positions on photographs (1~5).

injured, 312 buildings destroyed, and 71,291 buildings flooded.
Road destruction, bridge and river bank collapses, mountain landslides, and farmland damage subsequently occurred.
The type of damage caused by the heavy rainfall in Aichi
Prefecture is shown in Table 3. The left-bank of the Shin River
collapsed in Nishi Ward, Nagoya City causing severe flooding.
Inundation above floor level occurred 4,000 buildings in

Nishibiwajima Town, and 5,000 buildings in Nishi Ward.
Inundation above floor level was recorded for more than 2,000
buildings in Shikatsu Town and Shinkawa Town. Damage to public facilities amounted to 18,500 million yen, rivers (713 places, 12billion yen) and roads (459 places, 4 billion yen). Farmland was
flooded in various places and serious damage done to agricultural
crops, particularly vegetables and paddy rice. In Aichi Prefecture,

CHARACTERISTICS OF HEAVY RAINFALL AND FLOOD DAMAGE IN AICHI PREFECTURE FROM SEPTEMBER 11TH TO 12TH 2000

agricultural damage caused by the heavy rainfall amounted tosome 1.5 billion yen or more, and the total damage to 10 billion
yen.
Main flood damages that occurred in Aichi Prefecture fromthe time of the Isewan Typhoon in 1959 to present is shown in
Table 4. Damage in which flooding under the floor affected morethan 10,000 buildings occurred 4 times in the 1960s, and 8 times in
the 1970s. Although flood damage caused by heavy rain accompanying typhoons 8310 and 9118 has occurred recently, there was23

comparatively little damage done by inundation above the groundfloor level.
4.2

Flood Damage in Nishibiwajima Town and Nishi Ward,
Nagoya City
We made a field survey of the damage in these two places(Nishibiwajima Town and Nishi Ward of Nagoya City (Nakaotaiarea)), which suffered serious flood damage due to heavy. The
water level of the Shin River recorded at the Mizuba River Water
Level Observatory, the precipitation at the Nishikasugai WesternFire Department and the accumulated values are shown in Fig. 8.
The rainfall, which began to lessen during the early morning of the
11th was recorded as 338.0mm on the 11th and 84.5mm on the
12th, total precipitation 422.5mm. Moreover, the 12-hour precipitation from 15:00 on the 11th was 461.0mm, and the 1-hour precipitation 70mm at 21:00. The water level of the Shin River rose
rapidly from the afternoon of the 11th, the maximum of 623cm
being recorded at 3:00 on the 12th. After the heavy rainfall ended,
the water level of Shin River fell slowly.
The distribution of the depth (cm) of flooding of buildings in
the area investigated, fire department, a water level observatory,
and photographic positions are shown in Fig. 9. The depth of theflood is shown by the height of the flood mark from road surface.
Flood damage was severe in the 3km north-south and the 1km

Photo 1.

Flood mark on the glass of the door at the Nishibiwajima
Town Office (Hanasaki-cho, Nishibiwajima Town).

Photo 2.

Flood mark on the wall of the Meito dairy factory locatednorthwest of the JR Biwajima Station (Kaechi,
Nishibiwajima Town).

Photo 4.

Flood mark on the wall of an apartment building locatedsouth of the JR Biwajima Station (Asahi-machi,
Nishibiwajima Town).

Photo 3.

Flood mark under a bridge of the JR Tokaido Line (Yowa,
Nishibiwajima Town).

Photo 5.

Flood mark on the wall of the building of Takaoka Electric
Factorylocated about 500m west of Futatsuiri Station on
the Nagoya Railroad Nagoya line (Yoshino-cho,Nishibiwajima Town).

24

H. YAMAMOTO & K. IWAYA

east-west areas bounded by the Shin River, and the JR Tokaido,
the Nagoya Railroad Inuyama, and the Johoku lines. In Ashiharacho, Nishi Ward, where the bank of the Shin River collapsed andin the southwest of Nishibiwajima Town, the depth of flooding inbuilding exceeded 200cm. In the north-northeast area of
Nishibiwajima Town, the depth of flooding was shallow, less than
50cm in the northern part of the Nakaotai area.
The flood damage situation is shown in Photos 1-5. Photo 1
shows the flood mark on a glass at the Nishibiwajima Town
Office. The 140cm flood mark was reached at that public office.
Photo 2 shows the flood mark on the wall of the Meito dairy factory located northwest of the JR Biwajima Station. Here, flood markis at 180cm, and marks exceeding 200cm are present around thefactory. Photo 3 shows the flood mark under a bridge of the JR
Tokaido Line. It is at 350cm, and the road has completely subsided.
Photo 4 shows the flood mark on the wall of an apartmentbuilding located south of the JR Biwajima Station. Although thedepth of flooding is 172cm, because the ground floor of the building is a parking lot, there was no flooding of the apartments abovethat level. Photo 5 shows the flood mark on the wall of the building belonging to Takaoka Electric Factory located about 500m
west of Futatsuiri Station on the Nagoya Railroad Nagoya line.
Flood exceeding 200cm was recorded nearby, the deepest floodingin the entire area investigated. Serious damage also was caused byflooding at the Nagoya factory of Mitsubishi Heavy Industries
located north of Futatsuiri Station.
5. CONCLUSIONS
1)

2)

3)

4)

5)

6)

We collected a set of about 250 precipitation data recorded byvarious organizations and analyzed the characteristics of theheavy rainfall in Aichi Prefecture, September 11th to 12th
2000.
Daily precipitation at that time (428.0mm, records stated1891), maximum 1-hour precipitation (97.0mm, records stated1891), and maximum 24-hour precipitation (535.5mm,records stated 1971) in Nagoya (Local MeteorologicalObservatory) recorded the 1st highest record.
At the Midori Ward Engineering-Works Office, Nagoya City,
there first was a weak rain peak from predawn to early morning on the 11th, then heavy rainfall with a 1-hour precipitationof 100mm. Daily precipitation was 499.5mm on September
11th and 147.5mm on the 12th, and the total precipitation was
647.0mm.
From Midori Ward to Agui Town in the Chita district, NNE to
SSW direction the total precipitation exceeded 600mm over alarge area 6km wide by 20km long.
In Aichi Prefecture, the heavy rainfall moved slowly fromwest to east from the evening of the 11th through the earlymorning of the 12th. Heavy rainfall that exceeded 80mm wasprolonged from north and south in the area from Moriyama
Ward, Nagoya City to Agui Town, at 19:00, and strong rainfall also occurred in the surrounding region.
Flood damage was severe over an area 3km north-south and

1km east-west bounded by the Shin River, and the JR
Tokaido, the Nagoya Railroad Inuyama, and the Johoku lines.
In southwest Ashihara-cho, Nishi Ward, where the bank of the
Shin River collapsed, and in Nishibiwajima Town, flood
depth exceeded 200cm in buildings.
ACKNOWLEDGMENTS
We are grateful to the following organizations for precipitation and river water level data used in this study: theMeteorological Agency (Nagoya Local MeteorologicalObservatory), the Ministry of Land, Infrastructure and Transport(Chubu District Maintenance Office), the Aichi Construction
Department, Nagoya City (engineering bureau and fire fighting
office), Water Resources Development Public Corporation (Aichi
Water Management Faculty), and various fire fighting organizations, cities, towns, and villages, and the Japan Highway Public
Corporation (Nagoya Management Office).
REFERENCES
Aichi Prefecture, 2000. The damage situation due to heavy rainfall,
http://www.pref.aichi.jp/shobo/BOUSAI/index.html (in Japanese).
Fire Defense Agency, 2000. About the damage situation caused by heavy
rainfall from September 10, Heisei 12 (the 15th news),
http://www.fdma.go.jp/html/infor/120910ooame.htm (in Japanese).
Tokyo District Meteorological Observatory, 2000. Meteorological disasternews flash (Heavy rainfall caused by typhoon 14 and the front inHeisei 12 from September 11 to 12), (in Japanese).
Ushiyama M., T. Ishigaki, K.Toda and M.Chigira, 2000. Characteristics ofheavy rainfall disasters in Tokai district on September 11 to 12, 2000,
Jour. Japan Soc. Natural Disaster Sci., 22 (1), 1-11 (in Japanese withEnglish abstract).
Yamamoto H., S.Hayakawa and K.Iwaya, 1998. Characteristics of heavy
rainfall and agricultural disasters by typhoon 9709 in northern part of
Yamaguchi Prefecture, Jour. Japan Soc. Natural Disaster Sci., 17 (1),3-16 (in Japanese with English abstract).
Yamamoto H., K.Iwaya, K.Suzuki, S.Hayakawa and Y.Suzuki, 1999a.
Heavy rainfall disaster in Miyazaki Prefecture by typhoon 9719, Jour.
Japan Soc. Natural Disaster Sci., 18 (1), 55-69 (in Japanese withEnglish abstract).
Yamamoto H., K.Iwaya, K.Suzuki and S.Hayakawa, 1999b. Heavy rainfall
disaster in September of 1998 by akisame Front in Kochi Prefecture,
Jour. Japan Soc. Natural Disaster Sci., 18 (2), 213-226 (in Japanesewith English abstract).
Yamamoto H., K.Iwaya, K.Suzuki and S.Hayakawa, 1999c. Heavy rainfall
characteristics and flood disaster by typhoon 9810 in Okayama
Prefecture, Jour. Japan Soc. Natural Disaster Sci., 18 (3), 301-313 (inJapanese with English abstract).
Yamamoto H., K.Iwaya, K.Suzuki, S.Hayakawa and Y.Suzuki, 2001.
Survey on meteorological observations in northern part of Yamaguchi
Prefecture and using meteorological observation data, Jour. Japan
Soc. Natural Disaster Sci., 19 (4), 437-452 (in Japanese with English
abstract).