Trajectory of water, land and community developmentin the country of abundant rice fields and its future

Water chapter -History of Water Development in Japan1. Introduction

Japan is often cited as “a resource poor country”, but it is endowed with richwater resources, where the average rainfall is 1,718mm, nearly double the world
average of 880mm1). However, rivers in Japan have steep slopes with short lengths
compared to other rivers in the world (Figure 1), making flood control very difficult.
A Netherlands’ engineer, De Leek, who was invited to Japan in the Meiji Period
compared them to waterfalls, saying “This is not a river, but a waterfall”. As
such, flood control has been difficult, and continuous struggles with river control
have occurred throughout Japanese history, along with the development of paddy
farming.

Figure 1: River gradient in Japan and the world (Citation: Daichi eno Kokuin P58)

Seasonal fluctuations of rainfall are largely due to the effects of a monsoon
climate. In the past, rivers with steep slopes flooded and carried large volumes ofsediments, forming alluvial plains for people’s living (Figure 2).

In coastal areas,a long-term natural sedimentation expanded the land area from bay to lagoon tolake (Figure 3). People living in these river-formed plains constructed andexpanded irrigated cultivation land with their wisdom and hard labors, while
experience the repeating process of community abolishment and rehabilitation by
river flooding (Figure 4). People also enriched their livelihoods by utilizing waterskillfully in such ways as hydropower by water wheel or water transport whichhave been major parts of logistics until the modern period.

Figure 2: River and alluvial plain formation (image diagram)

Figure 3: History of Osaka Plain formation from Kawachi Bay (Citation: Daichi eno
Kokuin P60)

(Left) Jomon period (5,000~2,000 years ago) Kawachi bay became Kawachi
lagoon by soil sedimentation(Right) Yayoi ～ Kofun Period (1,800～1,600 years ago)
Sandbank enclosed the bay turning it into the freshwater Kawachi lake.
→Afterwards, the area became Osaka plain by artificial reclamation and othermeasures.

Figure 4: History of river utilization (Citation: ”History of river and humanrelationship” by Ministry of land, infrastructure and transport)

In this “Water Chapter”, we are going to focus on “water use technologies” thatare the root of agricultural and rural engineering, review the history of water
development that our ancestors have deeply engaged with from the birth ofcivilization to the present, and think about future prospects of agriculture and rural
engineering.

2. Birthofacivilization

by

paddy

farming(Jomon(14,500BCE-

300BCE)/Yayoi Period(300BCE-300CE))
During the Jomon Period, when hunting and gathering had been the center of
livelihood, people lived outside the river flooding inundation area. They lived inharmony with nature, collecting food by hunting, gathering, or fishing. People
started to live around rivers only after paddy farming technology was imported
into Japan. During the first half of the Yayoi Period, people started to obtain foodby modifying nature and practicing farming, drastically changing their livelihoodfrom that of the Jomon people. To construct and expand paddy farming areas,
tools such as wooden plows and hoes had been utilized. However, the technology
of modifying topography had not been fully developed, so paddy fields had beencreated in naturally formed semi-low land back marsh of alluvial plains andnarrow flatlands at the bottom of valleys, and villages had been constructed on
the semi-high land of natural levees adjacent to semi-low land. (Figure 2, Figure
2 in “Land Chapter”)
Paddy fields in the first half of the Yayoi Period had been formed by providing
small modifications to natural marshy areas, however, with the population growthand the increase of labor capacity in the village, people started to improve the land.
At Toro archeological site (late Yayoi Period, around 1st C. CE) in Shizuoka
prefecture, more than 50 rectangular plots of paddy fields surrounded with bundsof piles and sheet piles were discovered in an area of about 10 ha, having a dualpurpose ditch for irrigation and drainage in the center. (Figure 5) After the late
Yayoi Period, farm equipment with iron blades at the tip started to be adopted(Figure 4 in “Land Chapter”), and paddy fields had been expanded by developing
irrigation systems in natural landscapes through organized collaborative works.

Figure 5: Wooden piles at Toro archeological site (Citation: Daichi eno Kokuin P24)

3. Development of small rivers by an ancient state (Kofun Period (300CE538CE))
With the expansion of paddy farming, small villages were unified into a more
powerful state (Kuni), and labors were controlled by a ruler which enabled thedevelopment of engineering technologies including water intake from weirs,

construction of river embankments, and excavation of drainage canals byapplying technologies of immigrants mainly from Korea.
In the 4～5C. CE, a weir that could dam river water with a triangular wooden
frame filled with clay and gravel was constructed, as typically shown in a weir
(Figure 6) at Kodera archeological site (Ehime prefecture). Because such asimple weir could only endure the discharge of small rivers, a repeated process ofdestruction and reconstruction was continued during flood periods, when the areaof paddy fields and rivers grew too big for the weir. When the production of paddy
rice became stable, extra laborers could become mobilized in a centralized mannerby the first unified state, the Yamato Imperial Court. Together with technologies
transferred from the Asian mainland, numerous burial mounds (Kofun) wereconstructed from the 3rd century to the 6th century, mainly in the Kinki region (sometheories mention a moat surrounding the Kofun could be utilized for water storage).
Only pegs and ropes were available to survey and design the layout of Nintoku
Daisenryo’s Kofun (Figure 7) that is about 460 thousand m2 (13 times as large as
Tokyo Dome) (Figure 8). Experts propose that only human laborers with thesimple equipment of iron spades/hoes and straw made hampers to carry soils wereused to build the mound of 1.4 million m3, dig the double moats of 0.7 m3, andlay 5 million surfacing stones. This task would have taken 15 years and 8 months
with 2 thousand laborers per day2). In addition to laborers, about 6 thousandpeople were deployed at the construction site to provide food and make equipment
and clay images. Even with limited information transmission ability in this period,
the administration of the time had a very high construction management capacity
for controlling such large labor groups.

Figure 6: A weir at Kodera archeological site and its cross-sectional diagram(Citation: Daichi eno Kokuin P116)

Figure 7: Burial mound of Emperor Nintoku under construction by ancient method(imaginary diagram) (reproduced by Obayashi Gumi Co. Ltd., drawn by Kazuo
Hozumi)Figure 8: Regular and square area division by using poles and ropes (Citation:
Daichi eno Kokuin P158)

4. Ritsuryo system and introduction of Buddhism and civil engineering
technologies (Asuka(538-710CE)/Nara(710-794CE) Periods)
During the Asuka Period, the Ritsuryou based central control state was
gradually established after the Taika reform (645). This was accomplished byadopting the advanced culture and system of Tang, China, which evolved from aclan based society dominated by clans who exerted local control.
Adoption of the Kouchi Komin system (a system of state-owned land andpeople) and the Handen Shuju (rice field allotment) law showed that rice itself
was the financial base for the Yamato Imperial Court. Thus extension of paddy
fields and securing irrigation water became the absolute conditions for continuing
the Imperial State and maintaining the Ritsuryou system. In the 7th century, large
keyhole-shaped tomb mounds suddenly disappeared and high ranking priests wholearned Buddhism and civil engineering technologies from the Asian mainland
started to extend the construction of irrigation reservoirs using a valley-basedmodel. Creating an irrigation reservoir by enclosing the mouth of a valley is more
efficient because it decreases the soil volume moved for banking and digging
compared to a dig-in type reservoir. This method can lead to large flood damage
once the embankment is breached, so it required advanced civil engineering
technologies.

Sayama Ike reservoir (the oldest reservoir described both in the

Kojiki and the Nippon Shoki), which is said to have been constructed by a priest,
Gyoki, was confirmed to be constructed in 616 (early 7th century) by adendrochronological method at the time of modernizing a wooden sluice(modernization completed in 2001).
Manno Ike reservoir (Kagawa prefecture, Figure 9), rehabilitated by a priest,
Kukai, in 821, was breached in 1184.

It was rehabilitated after about 450 years,

however, breached again by the Big Ansei Earthquake in 1854, it had to be restored.
After raising the height of the embankment three times in 1905, 1927 and 1941,
the reservoir’s present capacity of 15.4 million m3 was reached in 1959. Even withrepeated breaching and rehabilitation of reservoirs, about 167 thousand irrigation
reservoirs have been identified as of 2019, and about 70 percent were deemed tobe constructed during the Edo Period or before.

Figure 9: (Left) Manno Ike reservoir - Many laborers compacting the embankment
using wooden rammers by the order of a leader(Right) A photo of reservoir rehabilitation (Citation: Daichi eno Kokuin P126, P163)

In 646, the imperial court issued an order that said “construct the embankments
in rivers for land development,” and flood protection works were implemented
with the forced labor of farmers. The Yamato basin had been the center of culture
and politics and an important traffic point that connected the Kyoto basin with the
Kizu river, and the Kii plain with the Yamatogawa and Kinokawa rivers, Namba,
and the Seto Inland Sea. In the middle of the Nara Period, small river channels
were improved in line with the chessboard layout of land allotment prescribed by
the Jori system. Channels were used for both irrigation water and shiptransportation (Figure 10).

Figure 10: River channels turn diagonally by the directions of Jori (Tawaramoto
town in Nara prefecture)(source: Modified part of a diagram in “Development of ancient basin and rivermanagement 3）” by Shigeki Matsuura)

5. Water management during the Shoen Period (8th cent. to 15th cent.)(after Heian Period)
During the early period after the enactment of the Konden Einen Shizai Law (alaw allowing farmers/developers to own cleared land permanently) in 743, manors
were mainly “self-developed” which meant they were developed and managed
directly by temples/shrines, aristocracy, and local lords. However, around the 10th
century, the “donated manor” became mainstream, which was a self-developedmanor donated by local lords to aristocrats and temples/shrines to avoid thepressure of the central government. The local lords instead became managers ofthe manor and seized the real power. As the area of manors increased, large scaledevelopment by the central government became difficult, and some people argue
that little progress was achieved during the Heian Period.
The size of a manor was usually about 50 chobu (around 50 ha.) and relied on
small rivers or reservoirs for irrigation. However, due to the neglect of proper
maintenance and repair, the area of Kataarashi (poorly cultivated) paddy fields
increased. For example, Todaiji temple owned 3,462 ha of paddy fields nationwide
in 950, however, only 212 ha. (6%) was actually cultivated4).
For more than one thousand years, from 794 to when the Heian Capital (Kyoto)
was moved during the Meiji Period, major commercial and physical distribution was
supported by water transportation for the capital of Japan, Kyoto. The
Yodogawa River is a large river with an abundant and stable flow due to theregulating functions of Lake Biwa. It became a major distribution path connecting
Kyoto with the coastal areas of the Seto Inland Sea where salt production sites,
forest areas, and farmlands existed. The Kamogawa River, which belongs to thesame Yodogawa River system, does not go through Lake Biwa and often
overflowed its banks. Emperor Shirakawa (1053-1129) called it one of threeissues that he could not control on earth, or Tenka Sandai Funyoi (the remaining
two issues were a roll of the dice and priest soldiers of Mount Hiei).
It is about 20km in a straight line from the northern tip of Biwa Lake to the Sea
of Japan, and on the eastern side of the lake, major roads went to the eastern partof Japan, thus water transportation in Lake Biwa played a major role inconnecting Kyoto with the Sea of Japan and the eastern part of Japan (Figure 11).
In particular, Japan’s front gate for envoys from the continent was the Hokuriku
region, where abundant rivers with snow melt flow were stable for paddy

cultivation and water transport. In this region, many manors were developed andrice was the annual tax. Fishery products and specialty goods, including lacquerware, were brought to Kyoto by water transportation, and supported the native
Japanese culture which bloomed during the Heian Period (until the modern period,
the side of the Sea of Japan was known as the “front side of Japan”.)
The Juugo irrigation canal system (Fukui prefecture, Figure 12), constructedin 1110 (Tenei Gannen), irrigated the 600 ha. manor owned by Kofukuji Temple
and was one of the largest irrigation systems of the time. According to a legend, aweir was constructed at the site (Naruka at present) where a deer cried three times
along the Kuzuryu River and a canal of 28 km was excavated along the path where
the deer went by the revelation of the Kasuga Myojin deity.

Figure 11: Transport on Lake Biwa (Citatoin: Webpage of the Imperial Household
Agency)Figure 12: Diagram of Togou irrigation canal system (Provided by Fukui prefecturein ”History of Fukui prefecture by illustration”)

Weirs and canals safeguarded manors by providing irrigation water andmaintaining paddy fields, so a God of Water was enshrined in the manor’s shrine
indicating that they were the very important to the manor. Shrines such as Oizeki
Daimyojin Shrine and Mizoguchi Daimyojin Shrine, shown in the map of
Izuminokuni Hinenosho (Hineno manor in Izumi province) (Osaka prefecture)
in Figure 13, that had canal paths in the shrine property were worshipped by usersof weirs and canals and those who engaged in construction works. They became asymbol to unite local groups through such events as festivals, ritual performances
praying for a good rice harvest, and rice planting Shinto rituals.

Figure 13: Diagram of Izuminokuni Hinenosho (Provided by the Archives andMusolea Department of the Imperial Household agency)

Use of water wheels started during the Heian Period5).. Sophisticated technology
adopted for a wheel in the Ujigawa River was recorded in the Kamakura Period
work “Tsurezure Gusa” (Essays in Idleness). Water wheels along Ogura Ike(Ogura pond), near the Ujigawa River, amounted to more than 100. Around the16th century poems about the natural scenery of rivers were often illustrated inbooks of famous places. Pumping apparatuses (Figure 14) such as hanetsurube
or nagetsurube, well buckets and treadmills respectively, continued to be used inmany local areas even after the Edo Period. Until fossil fuel energy became available
people had to invest a large amount of labor for pumping water. The Jyuren

Suisha Gun (multiple water wheel group) in Fukuoka prefecture’s Asakura
Town (Figure 15) is the oldest water wheel in Japan, constructed about 230 years
ago in 1789, and is still operating. It is renovated every 5 years by local artisans
to continue the traditional techniques into the present6). Operational, maintenanceand design techniques used for Asakura Jyuren Suisha Gun and the Yamada weir(a sloped stone faced weir) are applicable to developing countries. The late Doctor
Tetsu Nakamura transferred these techniques to Afghanistan, which has saved
lives beyond time and space7) by enriching the land of a foreign country.

Figure 14: Pumping apparatuses use in local areas (Citation：Daichi eno Kokuin
p.121, p123)(Left) Hanetsurube (Swing well bucket) : often used to pump water from a well for
cotton produced in the Kinki region.
(Middle) Nagetsurube (Throw well bucket) : used for emergency during drought(Right) Treadmill: used numerously in creek regions in Saga plain.

Figure 15: Water wheel(Left) ”Triple layered water wheel in Asakura” originally constructed before 1789
(source: Kyushu Regional Agricultural Administration Office, MAFF)(Right) Water wheel in Marwarid Canal modeled after Asakura water wheel , which
irrigates 40 ha with pumping of 1,200 ton/day.
(Citation: Homepage of Peshawar-Kai (a report from Dr. Nakamura on 2014.2.6))

6. Manor control by a band of warriors (Kamakura Period(1185CE-1333CE)~ Muromachi Period(1333CE-1573CE))
When privileges of Fuyu no Ken (the right of tax exemption) for a manager ofthe manor gradually expanded to Funyu no Ken (the right of denying the entranceof tax agents into the property), managers started to strengthen self-defense
capacity and use warriors to assure the control of their property without relying
on Kenmonseika (powerful temples/shrines and aristocrats). Yoritomo Minamoto
turned local landlords in the Kanto Region into Gokenin (vassals) and strengthened
the control of manors by appointing them as Shugo, provincial constables, of eachprovince and Jito, territorial stewards, for each manor or public territory. The rightof establishing and appointing Shugo or Jito by Yoritomo was authorized byImperial sanction (Bunji no Chokkyo) in 1185, when the Kamakura Period started.
The Kamakura Shogunate owned territories in the Kanto and Tohoku regions
where uncultivated land widely extended, and promoted the development of the
Kanto Plain, focusing on Musashi Province. The development of flood-prone
areas on the Kanto Plain was not possible with the prevailing technology level ofthe time. Large scale flood protection and reclamation works had been carried out
there since the Ritsuryo Period, but was limited to the mountainous western part.
During the Kamakura Period, double cropping, and the use of oxen/horses
with animal-power equipment were widely applied (Figure 16). Jito in local areas
followed the practice of the Shogunate to implement small scale development
works including river branches/mountain stream flood protection and irrigation
canal development. Warrior groups established bases of operations in lands aroundthe middle of the Kisogawa, Tenryu gawa, Fujigawa, and Shinanogawa rivers.
Warriors flourished during the Muromachi Period, such as Nitta, Ashikaga,
Hatakeyama, Hosokawa, Isshiki and Imagawa who were former Jitos who
expanded their territory by such developments.

Figure 16: Warrior and plowing by cow (Citation: “Story of Paddy Fields” P81)

During the Muromachi Period, Shugo took over the authority of provincial lordsof the manor and acquired the authority for controlling land and people as Shugo
Daimyo (Japanese territorial lord as provincial constable). Small and medium
farmers who were forced to work like slaves for manor lords improved their power
and position with the weakening authority of their lords. This led to the formationof a rural local self-government called So, made up of naturally formed, regionallygrouped settlements as a unit.

The capacity of farmers for self-reliance wasenhanced through community based collaborative management of irrigation water.
For example, the Imai Irrigation System in the Katsuragawa River in Kyoto, wasmanaged not by the lord, but by a farmer leader of the village, who formed thecontract of irrigation water use among three villages (1338-1342)4) Furthermore,
mountain forests and wastelands that were used as the sources for double cropping
fertilizer were incorporated into the Iriaichi (common land), which wascollaboratively managed by farmers. Through collaborative management of

common land and irrigation systems, the solidarity of So was strengthened. At theend of the Muromachi Period and during the Sengoku Period, farmers started toresist their Jito, or local lords, by military force in order to initiate Peasant/Ikko
uprising when their livelihood was threatened illegally.

7. Flood protection works by Sengoku Daimyo (Warring lord) (Sengoku
Period(1467CE-1615CE) ~ Azuchi Momoyama(1574CE-1600CE) Period)
During the Muromachi Period, Shugo Daimyo (territorial lords as provincial
constable) were appointed by the Muromachi Shogunate as rulers of the provinces.
However, when the Shogunate lost its power and control over Daimyo in 1467,
after the Onin War, Sengoku Daimyos (territorial lords during Sengoku Period)
emerged regardless of their birth or origin, by overthrowing their lords, controlling
the land and farmers of their territory, and competing to expand their territory toother provinces. Following the proverb of Chinese Spring/Autumn and the Warring
State Period; “those who govern the state well control water at first.” Sengoku
Daimyos integrated flood control works with developing new lands, by leading
subordinate warriors to increase rice production and enhance national wealth. With
the development of civil engineering technology through castle building and minedevelopment, inundating areas which had been left uncultivated were developedby embankment and irrigation canal building.
The Koufu Basin, where Shingen Takeda was based, was flooded every timesevere rain fell by rivers coming from all directions that changed their routes whenpouring down the alluvial fan. The flood of Kamanashigawa River in 1542
prompted Shingen to encourage flood protection measures by adopting the Koshu

School of flood protection (Koshuryuu Boukahou). As shown in Figure 17, theflow of the steep sloped Midaigawa River flowing from the west side of the Kofu
basin was fixed and controlled by the Kasumitei levee (Intermittent levee). The
levee was also called Shingen Zutsumi (G), after dissipating the flow of energy
by a Shogi (Japanese chess) piece shaped embankment called “Shogi Gashira” (Band C), absorbing energy by hitting the rock cliff “Takaiwa” (F) at the merging
point with Kamanashi River, and further reducing the water force by wooden
frames filled with boulders and stones or “Hijiri Ushi (Figure 17). After succeedingin controlling the river and reducing the flood damages, new paddy fields weredeveloped in formerly inundated areas. People in the domain living close to Shingen
Zutsumi were encouraged to migrate by tax exemption and labor contributions.
People in the domain were also mandated to engage in flood protection works toestablish a system of disaster management during flood periods. Shingen also
encouraged people to participate in the “Omiyuki Festival” (commonly called as
Omiyukisan), which was held before flooding periods to pray for safety against
floods. This festival also functioned to compact the embankment when many
beneficiaries stepped and carried a heavy portable shrine, which in the end becamea custom of operation and maintenance8) (Figure 18).

Figure 17: Flood protection measures by Koshuryu Boukahou method andKasumitei and Hijiri Ushi
Kasumitei are intermittent levees that allowed overflowing at the time of flood to
avoid breeching without disturbing the flow direction, and after flooding ended
overflown water upstream could naturally return back to the river.
(Citations: Mitsukan Water Culture Center, and “Daichi eno Kokuin”, p.136 andp.139)

Figure 18: “Omiyukisan” festival (provided by Kai City)-This festival is still held every year on 15th of April-

Experts consider that Shingen obtained advice about water engineering
techniques from flood control facilities at Tokou En (Dujiangyan Headworks) in theChengdu Basin in Sichuan Province, China.

In 1583, Narimasa Sasa also madedistinguished achievements in flood control by constructing the Sassa Tei (Sassa
embankment) and the Tonosama Bayashi (flood prevention forest) in the
Joganjigawa River in Toyama prefecture.

Techniques applied to his flood control

works are quite similar to Shingen’s and seem to have been learnt and provided by
Shingen’s engineers after the Battle of Nagashino in 15759). Kaneyoshi Ooki
who supported the Narimasa’s flood control works as a subordinate warrior, waslater employed by Kiyomasa Kato as a river engineering administrator after
the seppuku (suicide by disembowelment) of Narimasa. He supported Kiyomasa,
who became a feudal lord of Higo (Kumamoto prefecture) in 1588, through rivermanagement and new paddy field development works. Shingen’s techniques weremainly applied to an alluvial fan in the middle and upper streams of the river, while
those of Kiyomasa were applied to a plain in the middle and lower part of the riverto develop new paddy fields and implement land reclamation. The Hanaguri Ide(desilting canal) in Figure 19 was also created for this cause. While the roots ofKiyomasa’s techniques were similar to Shingen’s, his were improved according to
the conditions of local areas. Hyougo Naritomi, who suffered from the dispatch oftroops to Korea together with Kiyomasa, learned the techniques of Kiyomasa andlater applied them to develop the Saga Plain (an extremely flat land with anaverage gradient of one over ten thousand, a big tidal range of more than 5m on
average, etc.). He controlled the natural conditions of Saga Plain through the
integration of wide water use systems by creating flood control, irrigation anddrainage by connecting small and medium rivers, old creeks, inlets, and lakes
skillfully. During the Sengoku Period, river engineers migrated together withfeudal lords and transmitted techniques, which contributed to the development ofcivil engineering technology suited to regional characteristics.

Figure 19: Hanaguri Ide (Photo provided by Education Board of Kikuyou Town)
Lower part of a partition wall of bedrock has a hole like cattle nose ring, which
prompts spiral water flow and prevents silting of Aso Mountain volcanic ashes atthe bottom of a canal.

After Hideyoshi Toyotomi unified the country by ending war, he constructedFushimi Jyo Castle in Kyoto in 1594 and the Taiko Zutsumi (embankment) in the
Kizugawa River. He improved the water transportation system of the Yodogawa
River and transferred the flow of the Ujigawa River northward to separate it from

Oguraike Pond (Figure 20), prevent floods, and expand cultivation areas. He also
confiscated weapons from farmers by Katanagari (sword hunts), prohibited thechange of social positions (separation of warriors and farmers), and ended theact of Gekokujyo (overthrowing one’s lord). Taiko Kenchi (cadastral surveys) werecarried out to determine feudal tenure all over Japan, which established thefoundation for the centralized feudal control of the following Edo Period.

Figure 20: Improvement of Yodogawa River by Taiko Embankment(Citation: Suidono Ishizue in Yodogawa Suikeishi
Chapter 6 by ARIC)(Yodogawa Basin History)8. New paddy field developments by regional characteristics (Early Edo
Period (1603-1867))
Sengoku Daimyos (warlords) before the Edo Period could expand their riceproduction capacity (Koku), which was the financial foundation of their territory byinvading other provinces. However, during the Edo Period feudal lords could not
expand their territory, and thus engaged in developing inundation areas, such asalluvial plains and deltas, which encouraged using water engineering techniques
according to regional characteristics.
In the Osaka Plain and the Kinai Basin, old water engineering techniques called
Kamigata Ryuu (Kamigata School) progressed and were applied to Iruka Pondin the Nobi Plain in 1633 and the Wakasa Tei embankment in 1636.
Techniques to construct enclosing dikes (Wajyu Tei) (Figure 21) in the Kiso
Sansen (Kisogawa, Nagaragawa, Ibigawa) basin area of the Tokai region are of the
Mino School. Enclosing dikes were constructed to avoid flood and inundation in
Mino province as a means of self-defense. When Ieyasu Tokugawa (the first
Shogun of Edo Shogunate) ordered construction of Okakoi Tsutsumi in 1608, hesaid the “embankment of the Mino Domain side should be 3 jaku lower (about 90cm) than the one of Owari Domain side”, to protect the area of Owari Domain, theterritory of Tokugawa Gosanke (three privileged Tokugawa branch families). Afterthe heavy flood event in 1753, the Tokugawa Shogunate ordered Satsuma Domain
to construct Aburashima Shimekiri Tutsumi (closing dike) and other dikes. 947
Satsuma retainers were dispatched to Mino Domain for construction work. A large
sum of the construction cost was borne by Satsuma Domain and many victims
were sacrificed; 51 died of suicide by disembowelment for protesting the unjust

work, 33 died of illness, and a chief retainer, Yukie Hirata, killed himself by his
own sword after the work was completed (Horeki Flood Control Work).

Figure 21: Wajyu Tei and Mikakoi Tsutsumi in Kiso Sansen area
(Left) Mikakoi Tei and Wajyu Tsutsumi in Kiso Sansen （Before the rehabilitationof Meiji Period）(Up right) Start of Wajyu (Diagram)(Down right) Wajyu areas where three rivers of Kiso, Nagara, and Ibi merge.
(Citation: Website of Nagara Estuary Weir Management Office, Daichi eno Kokuin
p.96)

In the Sendai Plain, Jyuukichi Kawamura, a Christian, developed a large low
marsh area of the Kitakamigawa, Sakogawa, and Eaigawa River basin, by merging
three rivers (1616-1626) and established a network of water transport.
Development works applying western technology introduced with Christianity canalso be observed in such constructions as the Jyuanzeki Weir, constructed by
Jyuan Goto by applying a siphon technique in 1618.

The Kanto Plain was a large, inundated area, where rivers, lakes, and marshes
repeatedly joined and flows split in all directions. The Shogunate adopted the
Kanto School (also called Ina School) which followed the Koshu School (Figure17) to develop uncultivated parts of the Kanto Plain into a huge granary. This wasachieved by gradually shifting the path of the Tonegawa River, that originally
flowed into Tokyo Bay, to the east and making it flow into the Pacific Ocean(Eastward translocation of Tonegawa River (1594-1654) in Figure 22). A
feature of the Kanto School was a flood water retention approach to a meanderingriver that “meanders 48 times every 4 kilometers.” This school constructed
Kasumitei levees to overflow flood water to neighboring wastelands and protected
paddy fields with Hikae Tsutsumi levees. Another feature of the Kanto School wasin its use of old river courses. Chyuji Ina constructed Minuma Tamei irrigation
pond in 1629 by building the Hatcho Tei embankment (length of Hatcho: about870m) along an old river course in Minuma (Saitama City). In the Kasai Yousui
Irrigation Project (1660), a dead water section of the old Tonegawa River, causedby translocation, was utilized for an irrigation/drainage canal, and three irrigation
ponds were added to turn vast neighboring low marshy land into paddy fields. The
Kanto School was adopted as an official civil engineering technology of the
Shogunate, and was widely spread in Japan by local administrators dispatched allover Japan.

Figure 22: Old and new flow paths of Tonegawa River(Left) Old Tonegawa River course(Right) New Tonegawa River course
By translocating the Tonegawa River eastwards, not only flood control in a huge,inundated area of Kanto Plain could be realized, but also a stable water transportsystem from Edo (Tokyo) to the Tohoku region was established. (Citation: Webpage of Minuma Tanbo)

The shogunate and local domains encouraged the private sector to initiate newland development in the form of Murauke Shinden (Village contracted new paddy
field development) and Choninuke Shinden (merchant contracted new paddy fielddevelopment) by tax exemption/reduction and other measures. A typical project
under these shinden is the Gorobei Yousui irrigation system (1626-1631) in
Nagano Prefecture which Gorobei Ichikawa, who was once a samurai warrior,undertook in collaboration with numerous farmers and mine workers. Anothertypical project is the Fukara Yousui irrigation system (1668-1672), initiated by
the Fukara Mura village head, Gennojyo Ooba, and others in Shizuoka Prefecture,
which developed paddy fields of several thousand ha. by digging a 1,200 m tunnelof hard rock in the Hakone volcanic zone. One more typical project is the Kounoike
Shinden project (1705) initiated by a wealthy merchant family, the Kounoike inOsaka prefecture, which developed new paddy fields of 120 ha. by translocating
the flow of the Yamatogawa River, which once flowed into the Yodogawa River andthe ocean.
In 1609, the Population of Edo (the center of Edo Shogunate) was about 150
thousand, and securing drinking water was an important task, because the use ofunderground water was not easy due to Edo’s solid ground. Fujigoro Ookubo
constructed the Koishikawa Jyosui water supply system in 1590, which was later
extended to complete the Kanda Jyosui water supply system in 1629. At the timeof the third Shogun, Iemitsu Tokugawa, the population of Edo rapidly increased
with the establishment of the Sankin Koutai Seido (a system of alternate-year
residence in Edo by Daimyo lords) to force Daimyo lords, their family members andretainers to reside in Edo. In 1654, the Tamagawa Jyosui water supply system,
which withdrew water from the Tamagawa River, was completed to supply
abundant water to the people of Edo. The system diverted its water along theMusashino Daichi plateau, and significantly contributed to developing new paddy
fields on the plateau where water was scarce.
New paddy field development progressed rapidly based on the adaptation ofwater engineering technology to individual local features. During the first hundredyears of the Edo Period a total cultivation area of about 1.5 million ha. at the
beginning doubled in size to about 3 million ha.

9. Achievements of Irrigation and Drainage Systems in the Modern Period(Late Edo Period (1603-1867))
In the early 18th century, the population of Edo increased to over 1 million. After
serving as lord of Kishu Domain, Yoshimune Tokugawa became the 8th Shogun
in 1716, and posted an official bulletin board on Nippon Bashi in Edo to encourage
new paddy field development in 1722. To initiate further development of the vast
Kanto Plain as one part of the Kyoho Reform, he invited Yasobei Tamenaga
Isawa from Kishu (Wakayama Prefecture) in 1723 to become a government officialof the Shogunate.
Yasobei’s civil engineering techniques, known as the Kishuryu School, wereapplied in place of the Kantoryu School and were acquired from Saizo Oohata,
who followed the Kamigataryu School.
The Kishuryu school abolished Kasumitei School levees adopted by the Kantoryu
School and straightened meandering river courses with firm continuous levees andwater regulating works, including dredging and bank protection. New paddy
fields of 15,000 ha. were developed through various methods, such as reclaiming
Minuma Tamei pond and marsh lands along the canal, by destroying the Hatcho
Tei embankment, and separating irrigation and drainage, respectively.

Anotherdevelopmental method was alternative irrigation of water from the Tonegawa Riverthrough the newly constructed 60 km. long Minuma Dai Irrigation Canal (Figure
7 in Land Chapter). In the present, the Minuma Dai Irrigation Canal supplies

domestic water (drinking water) to the Tokyo metropolitan area through theMusashi Canal, developed in 1965. Water transport was very popular during the
Edo Period, however, water levels were too low for ship use in the downstream
reaches of the Minumadai Irrigation Canal after most of the water was withdrawn
for irrigation, while the flow in drainage canals increased as it went downstream.
To utilize canal networks for water transport, Minuma Tuusen Bori (Figure 23),a navigation lock, was constructed in 1731 (183 years before the completion of the
Panama Canal) to connect the downstream irrigation canal with the drainage
canal. Their water level difference was 3m.
Through the Minuma Tuusenbori lock, many materials such as rice, vegetables,
and wood were transported from the Minuma paddy fields area to major consuming
areas of Edo.

On the return from Edo to Minuma , ships transported manure(human waste) for use as fertilizer in the paddy fields. As such, Japan establishedan extensive system of material recycling involving the buying and selling ofwaste materials, which impressed foreign visitors with the clean sanitation
conditions in urban areas. In Western countries at this time, wastes were discardedon the streets as populations grew in urban areas (Figure 24), resulting in
deterioration of sanitary conditions, outbreaks of plague, and becoming a serious
social problem10).

Figure 23: Mechanism of Minuma Tuusenbori Lock
Locks in two locations control the height of ships by regulating water level(Citation: (left) Webpage of Minuma Tanbo, (right) Saitama City Education Board)

Figure 24: A London night scene where human waste is dumped on the head of
drunkard
William Hogarth (1738) (Citation: Daichi eno Kokuin p.75)

In 1854, Tuujun Kyo aqueduct, (Figure 25) based on arch principles, wasconstructed to deliver water to the water scarce Shiroito Plateau (Kumamoto
Prefecture). Sou Shouya (a leader of village headmen) Yasunosuke Fuda , usedunique planning and design in collaboration with a masonry group, financial support
from Higo Domain, and the participation of neighboring farmers. The aqueduct
made use of the technology of the time, including firm masonry techniques, aninverted siphon waterway, and a sedimentation discharge outlet on the aqueduct.

Figure 25: Water being discharged out of Tuujun Kyo (Citation: Website of MAFF)

10. Water engineering techniques of the Netherlands and modernization ofland improvement works (early Meiji Period (1868-1912))
At the end of Edo Period, about 1.87 million warrior class people received about
13 million Koku (1 Koku is about 150kg of rice) of salary, but it was reduced to
4.92 million Koku (less than 40%) by the Rokusei Kaikaku (salary system reform)of the Hanseki Houkan (the return of lands and people to the Emperor) in 1869.
Furthermore, in 1872 a conscription ordinance announced the introduction of auniversal conscription system, making professional warriors unnecessary. The Meiji
government promoted reclamation projects to create jobs for ex-warriors(Shizoku Jusan). Impoverishment of ex-warriors, particularly those of the lower
class, led to the breakout of the Seinan Senso War in 1877.
The Meiji government, after the dispatch of the Iwakura Mission (1871-1873) toobserve and inspect conditions of western countries, adopted a policy to promote
new industries (Shokusan Kogyo) under the slogan of “Fukoku Kyouhei”,
enriching the country and strengthening the military, by introducing modern
science and technology. Many water engineers from the Netherlands were
employed by the Meiji government, including Von Doorn and Johannis de Rijke(Figure 26).
In implementing the Asaka Sosui Irrigation Project in 1879 (Figure 10 of Land
Chapter), irrigation water requirements were calculated for the first time in Japanby the guidance of Von Doorn. Western technologies and materials were applied in
the construction such as a large volume of cement for strengthening weir banks,
tunnels, canal bottoms or other structures, dynamite and electric blasting, andsteam pumps for drainage of excavating tunnels for agriculture purposes. The
project opened a new era of applying and spreading modern western technologies
in agricultural and rural engineering works across Japan. Ichirobei Minami, borna son of a village leader in Usa (Oita Prefecture), was appointed as an engineer ofthe Ministry of Internal Affairs. He was engaged in the entire process of the Asaka
Sosui project, after being recognized for his technological capacity implementing
the Hirose Ide Irrigation Canal Project (started in 1869 as the first national
irrigation project) by Masayoshi Matsukata. Ide was appointed chief supervisor

of the Nasu Sosui Irrigation Project in 1885, conducted a survey for the Lake
Biwa Irrigation Project (1885 ~ 1890) and submitted an opinion document onwater use. His actions left footprints and he became known as a father of Japan’s
three biggest irrigation projects11).

Figure 26: Invited civil engineers from the Netherlands in early Meiji Period andtheir employment conditions/durations

(source: Partly modified the figure in p79 of “Nippon No Suisei” by Kouichi
Yamamoto)* Salary at the beginning of arrival to Japan, ** Estimate

The Meiji Yousui Irrigation Project （Figure 27）was initially planned by Yakou
Tsuzuki of Anjyo city at his own expense for developing new paddy fields. His plan
was submitted to the Edo Shogunate’s commissioner of finance in 1827. This plan
was supported by the Shogunate, but local support was not obtained due tocomplex conflicts of interests. The Tsuzuki family went broke by contributing 25
thousand ryou (currency unit of Edo Period, 1 Ryou =40~400 thousand yen atcurrent price, on average 1 ryo= 13 thousand yen.) to the project. Forty years
after the death of Yakou in 1873, Hamamatsu Okamoto, a merchant, andYohachirou Iyoda, a wealthy village head, separately submitted similar irrigation
project plans to Aichi Prefecture, which Aichi Prefecture merged into one and theninvited investors to raise funding. The project started in 1879, and its main canals
were completed in 1881. Masayoshi Matsukata named this project “Meiji Yousui”,
because it was completed through private financing and a representative projectof the Meiji Period. Extensively irrigated beneficiary areas became advanced
regions of farming in Japan and sometimes called Japanese Denmark.

Figure 27: Picture diagram of old Meiji Yousui headwork (in 1909) (Citation: Daichi
eno Kokuin p.104)

Water engineering technology of the Netherlands was based on the principle ofsecuring flow capacity by excavating a river channel and using low-water riverworks to stabilize the flow with water regulating facilities in channels.

With theguidance of Netherlands engineers, such works as the Kiso Sansen Bunryu
project (1887~1912) were implemented. Water engineering technology of theNetherlands had long been the model of modern flood control works.
With the progress of river improvement works, Goukuchi (unification of headworks)

wasimplemented.

Traditionally,

severeupstream ‐ downstream

confrontations based on customary water use practices occurred. In the
Jyoganjigawa River in Toyama Prefecture (Figure 28), after a devastating floodin 1891, the first large scale unification of head works based on a rehabilitation
plan by de Rijke was implemented. After this project, unification of head works
along with the implementation of river improvement work became popular in Japan,such as the Shichika Irrigation Canal Project in 1903 in Ishikawa Prefecture(Figure 29) and the Tozai Yosui Irrigation Project in 1907 in Okayama
Prefecture.

Figure 28: Conditions of Canal Excavation in Jyoganjigawa River (1892) (Suppliedby Midori Net Jyousai Yousui）

Figure 29: Name of “Shichika Yousui” came from the unification of seven water
intakes into one(Citations: (Left) Website of Tedorigawa Shichika Yousui Tochi Kairyouku, (Right)
Notthi Newspaper, Vol.7, Dec. 2007)

11. Shift to High-water River Works and Sophistication of Water Engineering
Technology (late Meiji Period (1868-1912))
In the middle of the Meiji Period, flood damage control using only low- water
river works introduced from the Netherlands became difficult. Thus, the flood

control system made a major shift to high-water river works that linearized river
channels, used high continuous embankments and led river flow to the sea throughdischarge channels. Such major shifting of river work systems was caused by:
deforestation for railway constructions between Tokyo and Kansai in 1889 andbetween Ueno and Aomori in 1891, associated construction booms, series ofdevastating floods in prospering downstream areas, and lowering needs of watertransport for low water control by railway construction.
In 1896 River Act (old act) was enacted and an integrated method of calculating
designed river flow by river engineering based on modern western science cameto be put into practice. As such, large scale flood control works, such as the
Yodogawa River Improvement Project (1897 – 1910) and the Ookouzu Bunsui
Diversion Project (1909 – 1922), were carried out, and water use systems
focused more on flood control rather than the Edo Period’s focus on agriculture.
During this period, Hidesaburo Ueno opened a course in agricultural and rural
engineering at Tokyo University in 1900 and the Land Consolidation Study Group(kouchi Seiri Kenkyu Kai), formerly known as the Society of Irrigation, Drainage,and Rural Engineering, was established. Land Consolidation Act was enacted in1899 and in 1905 irrigation and drainage works were specified as the scope of theact, from then on river engineering and agricultural/rural engineering were handled
as separate engineering groups.
In 1884, a sewerage system (Kanda Sewage) was constructed with guidancefrom de Rijke, and in 1887 a modern sewerage water supply system wasconstructed in Yokohama City with guidance from English engineer H.S.Palmer.
These technologies spread widely in Japan, and together with the start of chlorinedisinfection of drinking water in 1921, infant mortality rate drastically declined(Figure 30).

Figure 30: Water-supply System Coverage Rate (population coverage) in Japanand average life span/infant mortality rate
(Citation: ”Suiunshi kara Sekai no Mizue” , p.205)

With respect to hydropower generation, the start was in 1888 at Sankyozawa
power generation plant in Miyagi Prefecture for supplying electricity to spinningmill factories. In 1890, the operation of Touma Gendousho started to supply
smelting electricity to Ashio Copper Mine. Keage electric power generation
plant in Kyoto city, constructed by Sakurou Tanabe in 1891, utilized water from
Biwako Sosui. The electricity from this plant was used to start the operation of thestreetcar system in Kyoto. Initially hydropower generation systems were small
scale, but after the end of Russo-Japanese War (1905) electricity demands forheavy industries and domestic consumption increased rapidly. Large scaleconcrete gravity dams were constructed, along with long-distance high-voltage
transmission systems, for large capacity power generation.

12. River Developments by Constructing Modern Dams (Taisho period(1912-1926) ~ Showa period before the World War II (1926-1939))
Japan’s first dam, Hongouchi Koubu earth dam (H:28m), was constructed forthe supply of drinking water in 1889.The country’s first gravity dam, Nunohiki
Gohonmatsu Dam (H:33.3m), was built in 1900 in Hyogo Prefecture. The dam
was constructed of concrete rubble with the guidance of Englishman William
Burton and a design by engineer Toujiro Sato. Since then, for about 30 years up
to early Showa Period, concrete dams for drinking water or power generation had
been promoted in many parts of Japan concurrently with the establishment ofmodern industrialization.
For agricultural purposes, Honen Ike gravity dam (H=30.4 m, Figure 31) in
Kagawa prefecture was initiated in 1926 as a prefecture operated project. Sincethe base rock was deeper than initially expected, Midori Sugiura, with the guidanceof Toujiro Sato, an engineer of the Ministry of Agriculture and Forestry, adopted
multiple arch construction methods (rubble mortar masonry), the mostadvanced technology of the time even in the U.S. With the devotion of Mojiro Kaji,
the construction of Honen Ike was completed in 1930 by training technical workers
during night sessions and utilizing local embankment materials and 150 thousand
man-days of local people. The Japanese Society of Irrigation, Drainage, andReclamation Engineering was established in 1929.

Figure 31: Honen Ike Dam(Left) Multiple arch type Honen Ike Dam (Citation：Website of the MAFF)(Right) Kenchi Ishi masonry filled with rubble mortar (Citation :Yukikazu Tsuji

and others 25) )Regarding power generation, tall concrete dams were built using construction
techniques like those of today. In 1930, Komaki dam (H=79.2m), Japan’s firstconcrete dam, was built in Toyama Prefecture. It was followed by Senzu dam

(H=64m) in Shizuoka Prefecture in 1935, Tsukahara dam (H=87m) in Miyazaki
Prefecture in 1938, and Miura dam (H=84m) in Nagano Prefecture in 1942.
Japanese hydro-power generation systems shifted from channel types to water
reservoir types during this period.
In Heitou Prefecture, the southernmost part of Taiwan under Japaneseadministration, Nobuhei Torii, an agricultural and rural engineer, constructedNihou Shyu underground dam in 1921~1923 and converted about 3,000 ha ofbarren land into sugarcane fields. In Kanan Taishyu, Yoichi Hatta devoted himself
to irrigation planning, design, and construction supervision, and completed theconstruction of Usantou dam(H=56m) after 10 years in 1930. The dam used a

semi-hydraulic fill method and was the biggest dam in Asia at that time. It wasmore than 20 years earlier than Ishibuchi dam (H=53m), Japan’s first rock-fill
dam, which was constructed in Iwate Prefecture in 1953. The water scarce Kananplain became a big grain belt due to Usantou dam. Yoichi Hatta is respected as“the father of Kanan Taishyu” and on May 8th, his death anniversary, local
farmers and others even now conduct a memorial service in front of his grave(Figure 32).

Figure 32: Bronze statue of engineer Yoichi Hatta surrounded with flower offerings
from a memorial service in front of the grave(Photographer:

Lienyuan Lee (Shooting date: May 13, 2010))

As mentioned, after the late Taisho period, dam constructions started to progress.
In this period, urban water demands increased greatly with the progress of defense,
heavy-chemical, and machine industries. In addition, intake of agricultural water
gradually became difficult due to riverbed declines with the expansion of flood
control works and an unclear definition of water rights, which resulted in frequentwater use disputes. In 1926, the head of the civil engineering research center,
Nagaho Mononobe, proposed river water control projects based on an idea of“transforming flood water into resource”. This proposal was advocated for by thevote of a river subcommittee of a civil engineering council (subcommittee chair:
Akira Aoyama) in 1935, and officially became national government policy which

then led to the creation of multipurpose dam projects covering flood control andwater uses (water for industry, drinking, irrigation, and power generation). Suchinitiatives were influenced by the Tennessee Valley Authority’s (TVA)
comprehensive river development plan established by President Roosevelt to copewith the Great Depression in 1933. River water control projects, initially
implemented by prefectural governments with national government subsidy, anddams, including Okiura dam (Asase Ishikawa River), Koudou dam (Nishikigawa
River), and Sagami dam (Sagamigawa River), were planned and constructed. Tasedam (Sarugaishigawa River) was the first project directly initiated by the national
government in 1942.
After World War II, flood control projects began to be implemented in response
to big flood damages, such as Typhoon Kathleen in 1947, and large-scale flood
damages have decreased significantly since around 1965. New River Act wasenacted in 1964, and river control by consistent management from upstream todownstream with the basin as a unit was introduced. During the Taisho Period andpre-World War II Showa Period, Nagaho Mononobe’s theory was systematicallyincorporated into legislative systems, and a system of public management of riverwater was established in Japan.

13. Development of present land improvement technology (Showa Period(1945-1989) after World War II)
In November 1945, the government of Japan gave cabinet approval of
Emergency Reclamation Implementation Guidelines to cope with foodshortages, with the goal of reclaiming and developing 1.55 million ha. of land within5 years. Agricultural land reform began in 1946, and the idea of agricultural landownership turned into owner farmer principle.
enactedin1949,

targeted

cultivators

asLand Improvement Act,

principal

beneficiaries.

Land

consolidation associations created under Land Consolidation Act and irrigation
associations created under Irrigation Association Act were merged into Land
Improvement Districts. After the merger, reclamation projects began to bepromoted through Land Improvement Act. In 1950 an invitation was received fromthe Indian government to join the International Commission on Irrigation andDrainage (ICID), which was under preparation for establishment. After
participating as an observer, the Japanese government joined ICID after anapproval by the cabinet on Aug.24, 1951.

Membership in ICID came before thesigning of the San Francisco Peace Treaty in September 1951, and Japan took
its first step towards returning to international society through irrigation legislature,even before the restoration of her sovereignty.
After the enactment of the National Comprehensive Development Act in 1950,
large scale development projects, including the Aichi Irrigation Project, started
in 1957, have been implemented all over Japan using cutting-edge large civilengineering machinery. Support for such moves came from: active mobilization offinances through the borrowing of foreign currency from the World Bank and theuse of a special account system, the establishment of organizational frameworks
to mobilize special engineers from all over Japan through public corporations andnational project offices, and the increase of organizational capacity to functionallyrespond to problems during project implementation through engineers’ association,
universities, research institutes, and private sector. A technological system ofirrigation, drainage and reclamation engineering had been established through thecompletion of mostly technical documents, including a design standard forland improvement projects, in 1954, and revision of an irrigation, drainage andreclamation engineering handbook in 1957 (the first edition was in 1931).
After the high economic growth period of the latter 1950s, the sprawling
expansion of urban areas led to water supply confrontations between urban andagricultural use. As a result, the scope of technology in irrigation, drainage andreclamation engineering expanded from addressing just the physical issues of landengineering and water use to integrating regional development technology for
dealing with socio-economic situations, including multipurpose water development,
redevelopment of suburban areas, and the development of shallow sea area.
On Niigata plain in those days, lagoons, which were traces of the sea anddifficult to judge, lakes, swamps, and rivers were scattered around. Despite thehard work of submerging up to loin or chest in swampy fields (Figure 33), it
remained barren land. People would call the area “one cropping in three years”, or“production of Tori Matagi rice (rice even birds don’t eat)”. After 1947, Shinkawa
estuary pumping station (Figure 34), one of the world’s biggest, was completed,leading to the implementation of a series of land improvement projects which
contributed to transforming the submerged paddy fields’ area into the country’s
top grain basket, which in turn resulted in producing many listed companies,
including confectionery companies utilizing rice as raw material12).

Figure 33: Farming in submerged paddy fields sunk up to the chest (around 1945)(Citation: Website of MAFF)

Figure 34: Shinkawa estuary pumping station(Left) Aerial photograph of Shinkawa estuary pumping station

(Right) Main blade of the pump (4,200m: one of the world’s largest)(Citation: Website of Niigata prefecture)

After 1965 over production of rice became a problem, and the priority of land
improvements shifted from land reclamation for paddy fields to improving uplandfield irrigation systems. The Nansatsu project (Kagoshima prefecture) (Figure35) transformed the rough barren land of Shirasu or Kora volcanic soil to one of
the largest agricultural production areas through a large scale upland irrigation
system incorporating a natural lake (Ikeda lake) as a regulating reservoir.
During the same period, computer processing technology has been applied
for collecting information through either wire or wireless communication systems,
and from the early 1970s remote control systems have been introduced for
information collection. After the Okinawa islands were returned to Japan in 1972,
an underground water development study was initiated on Miyako island of
Okinawa prefecture, and with the efforts of agriculture and forestry engineer
Mutsuo Kurokawa and others, Minafuku underground dam was completed in
1979. Through practical experiments carried out at Minafuku underground dam,
underground dam technology was systematized, and water scarce elevated coral
reef islands in the Nansei Islands started to be developed by underground dams.

Figure 35: Photos of Shirasu soil and tea fields of Nansatu project
Poor volcanic ash soil of Shirasu or Kora became a leading production base of tea,okra, and broad beans through irrigation system development and landconsolidation (provided by: Agriculture policy department of Kagoshima Prefecture(left), Minami Kyushu City (right))

14. System renovation and measures against regional issues (Heisei period(1989-2019))
During the period of Heisei, rural structure and water use environments
surrounding agriculture have changed significantly, mainly due to the aging of rural
populations, urbanization, mixed rural/urban living, emergence of large scale
farmers by retirement of individuals from farming, and accumulation of farming
lands. New water resource development became difficult, and efficient use ofdeveloped water resources was requested. New projects were established including
the National Agricultural Water Reorganization Project, the Promotion of Regional

Water Function Project, and the Conservation and Consolidation of Natural
Environments Project.

Furthermore, small hydraulic power generation

systems have been introduced in water use facilities. In the Food, Agriculture,
and Rural Areas Basic Act, enacted in 1999, articles concerning multifunctionalroles of agriculture and consideration of the environment were added to theLand Improvement Act. In downstream areas of the Kuzuryugawa River inFukui Prefecture, consolidation of farmlands progressed, but problems started toemerge, including degrading of its water course, decrease of paddy field areas byproduction adjustment and farmland conversion, and water scarcity due to salt
damage. Thus, local water use assets were reorganized by pipelining the main
canal by National Project in 1999, and the agricultural water reorganization project
started to reallocate surplus water to surrounding areas, and promoted regional
water uses by utilizing old water courses, such as the “Seseragi water course” forfire prevention, and domestic water and landscape improvement (Figure 36).

Figure 36: Large scale pipeline and “Seseragi water course” in downstream areaof Kuzuryugawa River (Citation: Website of MAFF)

At this time, irrigation facilities that had been developed during the post war
period for food production began to require renovation and the focus of projects
shifted from new construction to renovation and repairs. For 5 years from 2007,
all national government developed facilities’ functions were evaluated to develop
and consolidate stock management related technology standards.

In 2011 a

project support system concerned with preserving and maintaining functions ofirrigation and drainage facilities was established during a significant reduction ofland improvement project budgets that began in 2010.

After the Great East Japan

Earthquake on March 11, 2011, disasters, including large scale earthquakes or
torrential rain have occurred in many parts of Japan. The Fundamental Plan for
National Resilience was adopted in 2018.
In 2015 a basic plan for food, agriculture and rural areas specified the promotionof ICT technology and underground water control systems to lessen humanlabor in water management and to achieve water use sophistication in accordancewith changes in farming systems. This plan was created to cope with variations in
irrigation periods, irrigation demands, and water management caused by aging
farmers and progress in land consolidation/intensification.

15. Conclusion
Agricultural and rural engineering, that may also be called the origin of watertechnology in Japan, developed and spread in accordance with specific local
conditions through the devotion and innovation of many engineers, who based theirtechnology on what was transmitted from continental Asia and spread during theancient period. Such cycles of transmission, spread and development have been

repeated. Water courses have not only been used for irrigation, but also fortransport and drinking water. Water wheels became a source of energy, which led
to the creation of a recycle oriented society in the early modern times. During themodern period, embankment technology originating in constructing ancient tombs
and ponds has been synthesized into a highly sophisticated dam technology, which
is used for industrial and urban water supply, flood regulation, hydropower
generation, and support for industries of a technology-driven nation. As of now, in
response to social demands, agricultural and rural engineering have expanded thetechnology’s scope from civil engineering oriented fields, such as geotechnicalengineering, structural engineering, and concrete engineering, to a comprehensive
technology of regional total coordination, fully utilizing the knowledge of facility
machinery, telecommunication, hydrometeorology, farming, environment andlegislation system.
In the field of agricultural and rural engineering, standardization of design has
been promoted through the rapid development of standard books, technicaldocuments, and the wide application of computers works, which have significantly
improved the efficiency of the technology. In order to pass various screening
committees for construction order and on-site inspection by the board of audit after
implementation, designs based on manuals are most uncontroversial, while
additional labor for accountability and risks are involved if innovative technology
should be applied. In our present society where information rapidly advances andthe mass production age has already been terminated, engineers should not always
depend too much on uniform standards and previous examples but act on essential
problems that meet the specific needs of on-site conditions and end users byapplying appropriate technology. To that end, labor productivity needs to be
improved by enhancing the efficiency of works involved by constant improvements
without always following conventional practices. Incidentally, the often cited“resource poor country” of Japan has advanced technology, human resources witha cooperative personality, and rich ocean energy and mineral resources at thebottom of the sea in the world’s 6th largest Exclusive Economic Zone13). Whentechnical difficulties are cleared, Japan will be able to self-supply energy andresources stably.
This chapter on water concludes with a message posted in a land improvement
district office for water engineers of the present age, the “Mizu Go Soku (fivewater.)” *1. It is water that always seeks its own direction and moves others by moving
itself.
2. It is water that has compatible characteristics that overcome any obstacle andaccumulate enough force to break through a rock, but also conforms to theshape of its container.
3.

It is water that makes others clean by its own purity and tolerates cleannessand dirtiness altogether.

4. It is water that offers unlimited services to production and livelihood throughforce and light without seeking rewards.
5. It is water that fills boundless oceans, evaporates into clouds and rain,changes into snow or hail, and freezes into a glorious mirror, but still maintains
its essential characteristics.

*It originated in Chinese classics and was the motto of Jyosui (Kanbei) Kuroda,
the founder of Fukuoka domain, and Ryoichi Sasakawa. Some called it the “Mizu
Go Kun (five water lessons)” or “Mizu Roku Kun (six water lessons)”.

Citations1.

Website of Dambinran.
http://damnet.or.jp/Dambinran/binran/TopIndex.html

2.

Project Team of Obayashi Gumi Construction Company. “Construction ofEmperor Nintoku Tomb by Modern and Ancient Technologies”. Website of
Obayashi Gumi.
https://www.obayashi.co.jp/kikan_obayashi/detail/kikan_20_idea.html

3.

Shigeki Matsuura. Kodai Bonchi niokeru Kaihatu to Kasensyori(“Developments and River Treatments in Ancient Valley”). Water Science,
Vol.2. No. 271983.

4.

Fujio Yamazaki. Suiden Monogatari (“Stories of Paddy Fields in Japan”). Rural
Culture Association Japan, 1996.

5.

Website of Ogura-ike National Land Disaster Prevention Project.
https://www.maff.go.jp/kinki/seibi/sekei/kokuei/oguraike/oguraike05.html

6.

Website of Asakura City, Fukuoka Prefecture.
https://www.city.asakura.lg.jp/www/index.html

7.

Nihonga Hokoru Sekai Kangai Shisetu Isan (“World Irrigation Heritage Sites inJapan”). Toho Press, 2019.

8.

Mitsukan Water Culture Center. Journal of Mizu no Bunka (”Water Culture”).
No.32, 2009.
https://www.mizu.gr.jp/archives/32_midaigawa2.html

9.

Kenichi Tanigawa. Kato Kiyomasa – Chikujyo to Chisui (“Kato Kiyomasa –Castle Construction and Flood Control”). Fuzambo International Company,
2006.

10. Website of Ministry of Land, Infrastructure and Transport, Sewage
Department, Sewage Document Office.
https://www.mlit.go.jp/mizukokudo/sewerage/crd_sewerage_tk_000008.htm
l
11. Website of Usa City, Oita Prefecture.
https://www.city.usa.oita.jp/index.html.
12. Monthly Journal Colombus. Toho Press. April, 2019.
13. Website of Agency for Natural Resources and Energy.
https://www.enecho.meti.go.jp/

References
1.

Akira Takubo. Suiden to Zenpou Kouenfun. (Paddy Fields and Keyholeshaped Tomb”). Nobunkyo Production, 2018.

2.

Koichi Yamamoto. Nippon no Suisei (“Water System in Japan”). Sankaido
Co.Ltd., 1996.

3.

Kazuko Toyama. Mizuno Bunkashi (“Cultural History of Water”). Chyuo Koron
Shinsha, 2013.

4.

Nogyodoboku Rekishi Kenkyukai. Daichi heno Kokuin (“Heritage of Land
Development”), 1998.

5.

Crowns Prince Naruhito. Suiunshi kara Sekai no Mizue (From History of Water
Transport to World Water”). NHK Publishing Co., 2019.

6.

Kasen Riyou no Rekishi (“History of River Uses”). National Land andTransport Ministry.

7.

Ryozo Matsuyama. Nihon no Nougyoshi (“Agricultural History of Japan”).
Shinpu Sha, 2004.

8.

Professor Takehide Hama, Kumamoto University. Presentation material of
Exchange Meeting of Kataribe. 28, Nov., 2019.

9.

Website of Ministry of Land, Infrastructure and Transport. Mizuriyou no
Rekishi (“History of Water Use”).
https://www.mlit.go.jp/mizukokudo/mizsei/mizukokudo_mizsei_tk2_000013.
html.

10. 100-Year History of Land Improvements. Heibon Publishing Co. 1977.
11. Toshio Kikuchi. Shinden Kaihatsu (New Paddy Fields Developments”).
Shibundo, 1963.
12. Association of Irrigation, Drainage and Reclamation Engineering. Nogyo
Dobokushi (“History of Irrigation, Drainage and Reclamation Engineering”).
1979.

13. Yukikazu Tsuji and Teruo Miyazaki. Hachijyunen woheta Maruchipuru Aachi
Konkuriito Damu no Honenike no Kenzo to Kaishyu (“Construction andRenovation of Multiple Arch Concrete Dam, Honen Ike Pond after 80 years”).
Concrete Journal. Vol. 29, No. 4, p.52-57, 2011.
14. Shigeki Matsuura. Senzen no Kasui Tousei Jigyo to sono Shakaiteki Haikei(“River Water Control Projects of Pre-war Period and its Social
Bakcgrounds”). Papers of the Research Meeting on the Civil Engineering
History in Japan, p.187-195, June, 1985.
15. Tokuhisa Matsumoto. Wagakuni Firu Damu no Sekkei Sekou no Hensen(“Transition of Desing and Construction of Fill Dams in Japan”). Doboku
Gakkai Ronbunshuu F, Vol.65, No.4, p.394-413, 2009.
16. Tadayuki Maeshiro. Miyakojima no Mirai to Chikadamu Kouroushatachi(“Future of Miyako Island and Meritorious Persons”). Shimatati, No. 64, p.4043, 2013.
17. Junya Hanada. Miyakojima ni okeru Nougyou Yousui Kaihatu no Rekishi to
Nougyou Suiri Sisetu no Keisho (“The Development and Inheritance ofAgricultural Water Facilities in Miyako-Jima Island). Journal of Water, Landand Environmental Engineering, Vol. 82, No.11, 2014.
18. Nihonga Hokoru Sekai Kangai Shisetu Isan (“World Irrigation Heritage Sites inJapan”). Toho Press, 2019.