6 Evolving History of Lake Biwa
and Yodo River Basin Management
Masahisa Nakamura · Yoshihiko Ogino · Michio Akiyama · Kunihiro Moriyasu

Abstract The management story of the Lake Biwa-Yodo
River Basin may be told in many diﬀerent ways. It is told
here as an intricate but dynamic history of management
challenges involving the upstream Lake Biwa region and thedownstream Yodo River region, with factual illustrations ofassociated policies, programs, and speciﬁc actions for water
resources development, ﬂood control, and environmental
and ecosystem concerns. These factual illustrations are alsointerpreted by the contributing authors with views reﬂecting their professional backgrounds, as well as their interestsand opinions on the conﬂicting and contested issues.
Keywords Water resources • Flood control • Lake Biwa
Comprehensive Development Project • River improvement plan • Basin governanceIntroduction
This chapter aims at presenting a general overview of theevolving history of Lake Biwa-Yodo River Basin (hereafterreferred to as the Biwa-Yodo Basin) water management,
M. Nakamura, Professor ()Research Center for Sustainability and Environment,
Shiga University, 2-5-1 Hiratsu, Otsu,
Shiga 520-0862, Japane-mail: m-nakamu@biwako.shiga-u.ac.jp
Y. Ogino, Professor Emeritus
Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku,
Sakai, Osaka 599-8531, JapanM. Akiyama, Professor
School of Environmental Science, The Universityof Shiga Prefecture, 2500 Hassaka-cho, Hikone,
Shiga 522-8533, Japan
K. Moriyasu, Former Managing Director
Biwako River Office, Kinki Regional Development Bureau,
Ministry of Land, Infrastructure, Transport and Tourism,
4-5-1 Kurotsu, Otsu, Shiga 520-2279, Japan

with special focus on ﬂood control, water resources
development, environmental, and ecosystem concerns. It
reviews the special features of the basin that have required
the region to overcome many historical challenges inmanaging this lake-river basin system.
Although the emphasis was given in this chapter tointroduce to the readers a factual review of the evolving
courses of events, the interpretive views expressed in diﬀerent sections of this chapter are not necessarily concerted,because the professional and disciplinary backgrounds,
and the thoughts and opinions toward contentious issues,
diﬀer signiﬁcantly among them. Speciﬁcally, Section 6.3
and part of Section 6.4 were contributed from a river engineering and planning expert focusing on ﬂood control. He
portrayed an oﬃcial view toward the need for judicious
implementation of the project components stipulated in
the Management Plan. Section 6.3 and part of Section 6.4
were contributed from an agricultural water policy specialist actively promoting the demand-side water managementthat he believes has been seriously lacking in the BiwaYodo Region. Section 6.5 was contributed by an economic
geographer with water management policy expertise on
the upstream and downstream dynamics on water andenvironment. Lastly, the remaining sections, 6.1 and 6.6,
and cross infusion of all the section contributions to collectively address the evolving water governance challenges
facing the Biwa-Yodo Basin, were synthesized by an environmental policy researcher specializing in lake basin
management. Lastly, the making of the Yodo River
Improvement Plan was prepared with the help of those
involved in either side of the contentious process.

6.1 Overview of Lake Biwa
and Yodo River Basin
6.1.1 Physical and Geographical Features
Lake Biwa had a naturally constricted and shallow river
stretch a few kilometers downstream of the southern edgeof the lake, restricting the ﬂow out of the lake to cause

Hiroya Kawanabe et al. (eds.), Lake Biwa: Interactions between Nature and People, DOI 10.1007/978-94-007-1783-1_6, © Springer Science+Business Media B.V. 2012

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6

Evolving History of Lake Biwa and Yodo River Basin Managementoccasional ﬂooding. The distance between this stretch andthe northern jurisdictional boundary of the greater Osaka
metropolitan region is only a few dozen kilometers. The
management history of Lake Biwa water may be characterized by the legacy of ﬂood control conﬂicts stemmingfrom this inescapable physical reality.
The lake measures 63.5 km in a north-south direction
and is divided into two sub-basins. It has a total surface
area of 674 km2, a volume of 27.5 billion m3, and a shoreline length of 235 km. Its catchment area is nearly ﬁvetimes the area of the lake itself, and its boundary more orless coincides with that of the prefecture, constituting 96%
of prefectural land. The catchment area consists of forestcovered hills and mountains (60%), paddy ﬁelds and otherfarmlands (25%), and urban and industrial areas. The prefectural capital, Otsu, located at the southern end of thelake, has an approximate population of 355,000. There are
ﬁve major rivers ﬂowing into Lake Biwa from the surrounding mountain ranges. There are also more than 100
small coastal streams and irrigation channels draining
into the lake, many containing irrigation return ﬂows andurban and agricultural runoﬀ from across the catchment
area, measuring 3,848 km2.
With Lake Biwa and its watershed occupying most of
the upper catchment portion, the Yodo River Basin is oneof the most extensive river systems in Japan. Encompassing
portions of six prefectural jurisdictions (Shiga, Osaka,
Kyoto, Hyogo, Nara, and Mie Prefectures), it has a total
catchment area of 8,240 km2 and the main river course
length of 75.1 km. The Seta River is the only natural outﬂowing river from Lake Biwa. The Seta River is called theUji River along a stretch of some 20 km within the Kyoto
Prefectural boundary. It is joined at the Hirakata conﬂuence point with the Kizu River from the east originating in
Mie Prefecture, and the Katsura River from the west originating in Kyoto Prefecture. Below this conﬂuence point is
the mainstream Yodo River stretching toward the Osaka
Bay in the south, for a distance of approximately 20 km.
The Ina River joins the mainstream Yodo River approximately 5 km upstream of the Osaka Bay. The Kizu, Katsura,and Uji Rivers contribute 18%, 15%, and 64%, respectively,of the ﬂow to the Yodo River at Hirakata. The Keihanshin(meaning Osaka, Kyoto, and Kobe) metropolitan region asa whole depends almost exclusively on the Yodo River forindustrial, municipal, and agricultural waters. Lake Biwa
accounts for water supplies totaling about 20 billion m3 per
year, serving as many as 14 million people. In addition, theSeta River water is also used for hydropower generation at
Uji, some 15 km downstream of the lake (see >Fig. 1).
The management history of the Yodo River System
may be characterized as that of conﬂict between the

upstream Shiga Prefecture and the downstream
Keihanshin area. For centuries, the communities immediately surrounding Lake Biwa experienced severe ﬂoodingof their agricultural ﬁelds, due mainly to the naturally
constricted and shallow river stretch a few kilometers
downstream of the southern edge of the lake. This naturalbarrier had been serving well in protecting the downstream population centers from inundation. The downstream and the central governments ﬁnally agreed in
1905, after a historic ﬂood in the Lake Biwa region in
1896, to dredge this stretch, and construct a weir structure (this original weir, named the Nango Weir, wasreplaced in 1961 by the Seta River Weir constructed at ashort distance downstream). With the construction of the
Nango Weir, and the ability to control the lake water level,
the frequency of ﬂooding and the associated ﬂood damages along the lake shore and inland were drasticallyreduced.

6.1.2 Flood Control
The Lake Biwa population always wanted the ﬂood water
to be quickly released downstream to save the riparianlands from inundation, while the downstream Osaka population always wanted the ﬂood water to be kept within
the lake to save the highly populated metropolitan area.
The Lake Biwa lowland farmers, however, had to yield tothe downstream political and economic powers over thecourse history. It was not until the record ﬂooding in 1896,
inundating the land around the lake for some 220 days,
when the downstream and the central governments ﬁnallyagreed to the construction of the Nango Weir. The weirserved the ﬂow control purpose well for several decades
till a new need arose, i.e., to supply water to the rapidly
growing urban and industrial centers in the downstream
region.

6.1.3 Water Resources Development
The major use of Lake Biwa water had historically been forpaddy irrigation, by channelizing and barraging the riparian feeder rivers and the outﬂowing Yodo River and its
tributaries. It was in the late-nineteenth century when theﬁrst large-scale water resources development project was
implemented. Realizing the potentially serious decline not
only of its political status but also its economic status, thethen newly appointed Kyoto Governor foresaw the need todevelop the Kyoto economy by linking Kyoto with Lake
Biwa by a canal to withdraw the lake water. He engaged aEvolving History of Lake Biwa and Yodo River Basin Management

6⊡ Fig. 1
Bird’s eye view of the Lake Biwa and Yodo River Basin (Niu, Daido-River, Kawakami Dams, proposed to have been
constructed in an earlier plan, have been subjected to debate whether or not to proceed with the plan. Yono River Dam,also in the earlier plan, was agreed not to be constructed. Amagase Dam and the Seta River Weir have been agreed to berenovated. See Section 6.5 for details).

young engineer who succeeded in constructing the canalconnecting Lake Biwa to Kyoto in 1890, saving this waterconstrained city from a serious economic decline.
The second large-scale water resources development
project took shape when Osaka began to regain its industrial strength in the early 1950s after the Second World
War devastations. The existing water rights from the Yodo
River ﬂow had already been exhausted, however, and by
the early 1960s, Osaka was already eyeing the use of theabundant Lake Biwa water.

6.1.4 Lake Biwa Comprehensive Development
Osaka wanted more lake water to be released downstream,
particularly during the drought periods, through the existing Nango Weir, which had been constructed more forﬂood control purposes than for water resource development. It was replaced in 1961 by the Seta River Weirconstructed at a short distance downstream both for ﬂood
control and water resource development. More than adecade of heated political exchange took place between
the downstream local governments (mainly Osaka
Prefecture and Osaka City), the National Government,
and the Shiga Prefectural Government with regard to thepotential gains and losses of this action, in terms ofaccrued economic beneﬁts, ﬁnancial burdens, and environmental impacts of transforming Lake Biwa into a sortof man-made reservoir. Increasing the amount of ﬂow
through the Seta River channel meant the need forenlargement of the weir capacity, as well as for dredging of
the constricting channel. However, reconstruction of theweir to provide a greater water volume in the lake, in preparation for extreme droughts, also meant an increased

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Evolving History of Lake Biwa and Yodo River Basin Management

probability for ﬂooding damage around the lakeshore
lands. Combined with the need to protect the downstream
Yodo River from still imminent ﬂooding, the ultimate
solution was to construct a levy around the lake toimpound more water within the lake in anticipation of
possible droughts, and in preparation for protecting both
the downstream Yodo River and Lake Biwa coastal areasfrom ﬂooding.
This agreed scheme of Lake Biwa water resource development is called the Lake Biwa Comprehensive Development
Project (hereafter referred to as LBCDP, see Section 6.4 fordetails).

6.1.5 Evolving Challenges
The Shiga Prefecture was a reluctant party in LBCDP,
insisting the need for totally rehabilitating the coastal
infrastructure such as water intake, ﬁshing and navigation
facilities, as well as the possible adverse eﬀects on the
shoreline ecosystems, particularly, on the habitat environment of ﬁsh species, including the indigenous ones. The
reluctance of the Shiga Prefecture, however, stemmed
more from the psychological rejection of its residents tothe notion that the upstream region had to continue toendure a long history of suﬀerance to occasional ﬂoodingof its coastal region for the beneﬁt of the downstream
region, and then having the downstream region demanding the release of more water exclusively for its own convenience and economic gain.
While the LBCDP accomplishments have brought
about signiﬁcant overall beneﬁts to the Biwa-Yodo region,
there remained unresolved legacies, unﬁnished businesses,
and emerged challenges necessitating such new policy
initiatives. The Lake Biwa Comprehensive Conservation
Plan, (hereafter referred as LBCCP), is one, and the Yodo
River Improvement Plan (hereafter referred to as YRIP), is
another. LBCCP is a plan being developed and implemented by Shiga Prefecture and, therefore, touches little
on the issues facing the entire Biwa-Yodo Basin, while
YRIP is a plan being developed as a river management
plan, rather than a river basin management plan, to be
implemented as a trans-jurisdictional national government plan. Among the important issues facing LBCCP is
ﬁnancing of the component programs pertaining to,basically, restoration of the lake ecosystem. Among theimportant issues facing YRIP, on the other hand, isthe development of an institutional framework more suitable for basin management than river water managementthat will be able to meet the emerging governance challenges (see, Section 6.5 for details).

6.2 Brief History of Lake
Biwa Flood Control
6.2.1 A Legacy of Lake Biwa Flood Control
Two Major Issues Facing Lake Biwa—Yodo
River Flood Control
Within the Yodo River Basin, there are several climatic
zones aﬀecting the precipitation patterns of the three major
sub-basins, one in the north covering the Lake Biwa watershed, another in the east covering the Kizu River watershed,and still another in the west covering the Katsura River inthe west. The Yodo River, which originates at the conﬂuence
point of the three tributary rivers, however, has one of themost stable ﬂow characteristics among the major rivers inJapan, thanks to Lake Biwa acting as a huge natural regulating pond. Because of this stable ﬂow, the Yodo River had
historically been able to serve as a major transportationroute of agricultural products from across Lake Biwa andother commercial goods between the upstream eastern
Kyoto along the Kizu and Uji Rivers, all the way down to
Osaka Bay. It also served as a mode of passenger transportation between Kyoto and Osaka. With Lake Biwa providing
ample and stable ﬂow throughout the year, the Yodo Riverhas had an enduring impact on the economic, cultural, andpolitical dynamics of the entire Kinki Region. The evidence
remains today in the form of thriving metropolitan regionsof Kyoto, Osaka, and Kobe. The water management of the
Yodo River System, however, has historically been dictatedby two major ﬂood protection concerns, namely:••

Reduction of ﬂooding risks endured by the Lake Biwa
shoreline and lowland communities for the upstream’s
sake; and
Improvement of river embankments with stronger andhigher levies along the Yodo River and its tributaries
for the downstream’s sake.

These issues have not yet been fully resolved, as discussed later in this chapter.

Constraining Topography of Lake Biwa
There are some 120 or so in-ﬂowing rivers to Lake Biwa
originating from the surrounding mountains. These shortand steep rivers discharge the collected precipitation fromthe mountainous terrains almost instantaneously into
Lake Biwa, quickly swelling the lake to impede the inﬂowing river water, eventually causing ﬂooding not only along
the coastline, but also along these river channels. A more

Evolving History of Lake Biwa and Yodo River Basin Management

6⊡ Fig. 2
Inundated areas in red
during the Great Lake
Biwa flood of 1896
(The land occupied by theprefectural government
offices in the center ofOtsu City was completely
inundated. The surface
area of Lake Biwa isestimated to haveincreased by 30%).

serious concern is that the Seta River, the only outﬂowing
river from the lake, is naturally constricted a few kilometers downstream of the lake outlet, at the protrusion of Mt.
Dainichi. This constraining topography causes the lakelevel to rise rapidly, and inundate the surrounding land
during heavy rainfalls periods related to typhoons andother climatic conditions, historically causing hardships to
paddy farmers.
A record-breaking ﬂood took place in September 1896.
The rainfall over the period of just 10 days from September

3 to 12 was 1,008 mm, or more than half the usual annual
average of 1,900 mm, with a dramatic one-day record of 597
mm on September 7 alone. The lake water level rose up to
3.76 m above the normal level (designated as the Biwako
Basic Surface Water Level, or B.S.L.), and caused unprecedented ﬂooding around the lake, inundating most of thetowns and villages around the lake and along the inﬂowing
water courses. Altogether 14,800 hectares are recorded tohave been ﬂooded, with the inundation lasting for as long as
237 days before completely being receded (>Fig. 2).

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Evolving History of Lake Biwa and Yodo River Basin Management

Upstream–Downstream Conflicts overDredging of Seta River
Since the mid-nineteenth century, there have been anumber of proposed attempts to dredge the Seta River toincrease its discharge capacity for the lake water, particularly to compensate for the above-noted natural topographic ﬂow constriction. These proposed attempts by
the upstream farming communities met with severe
opposition by the political powers and commercial interests in the downstream population centers. The simple
dredging along the shallow and constricting stretch of
the Seta River would mean sending ﬂood water downstream, causing damages to population and commercial
centers, rather than to upstream farmland and villages.
The downstream region wanted the ﬂood water to be
kept upstream as long as possible, allowing its gradualrelease over a prolonged time. The evolving history of
events to overcome this extremely complicated and conﬂicting case of ﬂood management is reviewed in the next
sections.

6.2.2 From Premodern to Early
Modern Times
Premodern Times (Seventeenthto Nineteenth Centuries)
The ﬁrst recorded event of Seta River dredging was in
1670. Responding to petitions from people living near thelake, the shogunal administration carried out the dredging. Subsequent appeals for dredging were repeatedly
refused, one reason being that the dredging destroyed an
important strategic point on a military route for the
defense of Kyoto. Another was that a reduction in the lakewater level also aﬀected the defenses of the then-important military strongholds of Hikone and Zeze (Otsu)
Castles. A ﬁnal major reason was the objections of people
living downstream, who feared a greater risk of ﬂooding.
During the two centuries before the modern era, 20 formal
requests for dredging were made, but it was only allowed
ﬁve times. It was twice carried out at the cost of the local
administration, with private contributors bearing the costburden for the remaining times. Even when local people
were willing to organize and pay for the work themselves,the administration refused permission.
The people living along the lake grew frustrated withthe administration for ignoring their heartfelt petitions andtook matters into their own hands. Under the guise of
harvesting freshwater shellﬁsh, Corbicula sandai, theylaboriously dug up the river bed and carried away the
sediment. The administration at that time did not knowwhat to do about the dissatisfaction of the lakeshore residents. As a kind of response to the long-ignored ardent
wishes of the people, the boats were exempted from taxation of the clam harvest until the modernization started.
This exemption was practically an acknowledgement thatthe eﬀect of the clam ﬁshing boats was equivalent to dredging, and was instituted to appease the local people.

Early Modern Period
In the very ﬁrst year of the Meiji government era (the ﬁrst
modernized government, 1868–1912), there was a major
ﬂood that the local government (Otsu Prefecture) took as acue to undertake the ﬁrst large-scale dredging since 1831 of
the Seta River. While the dredging took place to some extent,
the lake remained placid for some years. The lake level rose
to 2.71 m above B.S.L. in 1885, however, causing extensive
ﬂooding both around the lake and downstream along the
Yodo River. During May to September in 1889, the lake levelremained at a height between 1.4 m to 2.0 m above B.S.L., asituation that made paddy plantation impossible around thelake. Coincidentally, in the same year, the construction of the
Seta River Bridge (length 405 m) was started by the National
Railways Tokaido Mainline. Being very concerned that theeighteen pillars of the bridge might interfere with the outﬂow from Lake Biwa, the Lake Biwa Flood Control Alliance
Committee was organized to carry out campaigns to petition
the national and local governments for a reduction in thenumber of bridge pillars. Determined to ensure the issue wasresolved once and for all, the slogan was “construct the bridge
pillars that do not impede the ﬂow.” Joined by the Shiga
Governor, this campaign turned into a movement to petition
for instituting the Seta River dredging works. A series of petitions was presented to the national government to allow for
the dredging, to receive the state subsidies, and to have aproject established under direct government control.
At the same time, however, having experienced ﬂood
damage in 1885, the downstream residents along the lower
reaches of Yodo River also feared that dredging would put
them at greater risk. The Yodo River Improvement Action
Association was formed, and petitioned for cessation of the
Seta River dredging, and for the national government toinitiate a large-scale Yodo River improvement project. These
opposing interests evolved into a serious political issue.
Facing these circumstances, Mr. Tohru Okoshi, thenational government oﬃcial appointed as governor of Shiga
Prefecture, who feverishly believed in the need for the dredging to take place, sent repeated appeals for dredging of theEvolving History of Lake Biwa and Yodo River Basin Management

Seta River to the Home Minister during 1891–1892. It ﬁnallyresulted in the decision by the Home Ministry to carry out
the dredging during the next year (1893) to the extent that it
would not increase the ﬂooding danger downstream.
Governor Okoshi invited members of the downstream Yodo
River improvement action association in Kyoto and Osaka
to attend a gathering to celebrate the completion of dredging. In his address to the gathering, he said, “Now, let’s join
forces and push for a greater Yodo River improvement.”

6.2.3 Dawn of Full-Fledged Lake Biwa
and Yodo River Flood Control
Infrastructure Development
Yodo River Flood Management Works Report:
Founding Report of Future Lake Biwa FloodControl Policy
Being catalyzed by the successful dredging undertaken in
1893, the Meiji government urgently formulated a plan for
Yodo River improvement. The plan was developed on thebasis of the major ﬁndings of the Yodo River Flood Defense
Works Report compiled mainly by Dr. Tadao Okino, headof the Osaka Construction Field Oﬃce of the Home
Ministry, in which the Lake Biwa water levels were extensively analyzed. This report also was the foundation forlater basic policies to control ﬂooding around Lake Biwa.
The main thrusts of the report included the following:••

Reducing Lake Biwa’s normal water level by increasing
the discharge rate of the Seta River channels during
the winter period;
Constructing a weir across the Seta River to enable adjustment of discharge rates and lake water levels;

In essence, the Report stipulated the following threebasic principles that formed the basis of an engineering
approach in Lake Biwa ﬂood water management and therelated policies; namely:•••

To reduce the Lake Biwa water level before ﬂooding
occurs, so as to increase the receiving capacity of thelake for the expected inﬂuent ﬂood ﬂows.
To reduce the duration of the Lake Biwa ﬂooding risk
by increasing the draining ﬂow of the Seta River, thereby reducing the lake’s swelling water volume.
To reduce the downstream ﬂooding risks by completely closing the weir at times of peak discharges to Yodo
River from the Katsura and Kizu Rivers.

For ease of reference, a chronology of Lake Biwa-Yodo
River management activities is provided in >Table 1 anddiscussed in the following sections.

6

Yodo River Flood Management Works(1896–1909): River Improvement and Weir
Installation
Japan’s ﬁrst Rivers Act was passed by the Imperial Diet in
March 1896. Following this legal basis, the Yodo River
Improvement Scheme was implemented by the national
government as outlined in the Yodo River Flood Defense
Works Report. Including the whole upstream and downstream river systems from Lake Biwa to the mouth of the
Yodo River discharging into the Osaka Bay, this was the ﬁrst
river improvement project in Japan based on a comprehensive river plan. From 1900 to 1908 the project included thethorough dredging of the Seta River and the ﬁrst construction of a weir in 1905. Still in force after construction of a
new replacement weir in 1961, these principles stipulated in
the Plan still operate today (>Fig. 4).
The old weir (the Nango Weir) was opened and closed
entirely by manual labor. It took 1 day to completely open
the weir, and 2 days to completely close it. Nevertheless,the weir operation decreased the ﬂood damages. Over theperiod of 30 years prior to the weir installation in 1905, theLake Biwa ﬂooding occurred 17 times, and twice, the lakewater level rose to more than 2.4 m over the normal level.
Over the period of 14 years after the weir construction anddredging, relatively small-scale ﬂoods occurred twice, withthe lake water level rising to only as high as 1.5 m over thenormal level, an impressive contribution by the improvement works (see >Fig. 3).

Yodo River Control Project Phase 1(1943–1952): Dawn of Lake Biwa Region
Comprehensive Development
During the First World War, Japan made great strides inindustrial development, particularly with regard to theincreased scale of hydroelectric projects. Industrial development was also accompanied by hugely rising demand
for water. Along the Yodo River, people also sought forways to make more eﬀective use of Lake Biwa water. By
1940, the Yodo River Control Project was announced, withthe aim to control ﬂooding and promote water supplies.
When the Phase 1 of the Project was launched in 1943, thewartime diﬃculties, including the lack of supplies for construction works, and their steeply rising prices, hindered
the needed rapid achievements. Thus, the plan aimed tokeep the lake level lower than usual, as follows:•

For ﬂood control purposes, the Lake Biwa water level(measured at the gauging station located at the Torii
River conﬂuence point to the Seta River) was to be

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Evolving History of Lake Biwa and Yodo River Basin Management⊡ Table 1
History of Lake Biwa – Yodo River flood management plans
Name of plan, duration
1. Yodo River Improvement
Works (1896–1909)

Objectives and outlines¨ Seta River Dredging•

Increase channel width to 110 m and depth to more than 3.0 m•

Increase discharge capacity from 50 to 200 m3/s•

Weir construction (completed in 1905)¨ Lake Biwa planned water level•
2. Yodo River Control Project
Phase I (1943–1952)

Pre-lowering of water level (water level to be reduced by 0.9 m below normal
during flood seasons)¨ Seta River Dredging•

Increase discharge capacity from 200 to 400 m3/s

¨ Lake Biwa planned water level

3. Yodo River Improvement
Master Plan (1957–1967)•

Planned high water: Torii River Mark of +0.8 m•

During receding inundation period: Torii River Mark +0.3 m•

During flooding: Torii River Mark of ±0.0 m•

Ensure downstream water supply: Torii River Mark of ±1.0 m (Plan Phase 1)¨ Seta River Dredging•

Increase discharge capacity from 400 to 600 m3/s•

Construct new weir (completed in 1961)

4. Yodo River System Project
Master Plan (1971–2007)¨ Seta River Dredging

5. Lake Biwa Comprehensive
Development Project(1971–1997)¨ Seta River Dredging••

Increase discharge capacity from 600 to 800 m3/s

Increase discharge capacity from 600 to 800 m3/s

¨ Lake Biwa planned water level•

Planned high water level: B.S.L. +1.4 m•

Flood period level: Setat B.S.L. –0.2 m during period between June 16 andAugust 31, and –0.3 m during period between September 1 and October 15(lowered from previous ±0.0m)•

Water supply discharge level: Planned low level B.S.L. –1.5 m, with financial
compensation measures to be made for the level lower than B.S.L. 2.0 m¨ Lake periphery flood management•
6. Yodo River Infrastructure Master
Policy and Yodo River Infrastructure
Master Plan (2007 – present)•

Construction of levy and pumping stations, etc.

¨ Seta River Dredging•

Increase discharge capacity from 600 to 800 m3/s

maintained at +30 cm, above the normal level of ±0cm, during the nonﬂooding period. The water level
was allowed to rise up to +80 cm for ﬂood inﬂows during the ﬂooding period.
For the water supply purpose, the planned low waterlevel was set at −100 cm. The amount of water to beheld within the lake between the low water level of−100 cm and the high water level of +30 cm (during

the nonﬂooding period) would be 920 million m3
for downstream domestic, industrial, and agricultural uses.
Although carried out under direct government control, many problems worked against completion of the
project in 1952. Dredging of the Seta River remained acontinuing major challenge.

Evolving History of Lake Biwa and Yodo River Basin Management

6haInstallation of Seta River Weir in 1905

16,000Areas of14,000inundation (ha)12,00010,000
8,000
6,000
4,000
2,000

year

1884 1885 1889 1896 1903 1907 1917 1938 1953 1961 1965

the highest water level
during flood (m)2.12 2.72 2.00 3.76 1.47 1.29 1.43 1.09 1.00 1.08 0.92

Duration ofinundation (days)

30
60
90
120
150
180
210
240
270
day

⊡ Fig. 3
Extent of inundation before and after the Seta River Weir installation.

⊡ Fig. 4
Seta River Weir today(The Seta River Weir wasconstructed in 1961,
replacing the Nango Weirconstructed in 1905).

Yodo River Improvement Master Plan
(1957–1967) and Installation of New Weir
In September 1953, Typhoon No. 13 inﬂicted signiﬁcantdamage to the large areas of the Yodo River catchment. This

prompted the development of the Yodo River Improvement
Master Plan, which included the revision of the discharge
capacity targets for the Yodo River System. The plan included
even more thorough dredging of the Seta River and theconstruction of a new weir. The outdated weir, completed

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Evolving History of Lake Biwa and Yodo River Basin Management

Rain
Peak
Water Level

380

Approximately 1 day

Yodo River FlowPeak

⊡ Fig. 5
Time difference between
the peaks, respectively,of the Yodo River flow
and of the Lake Biwa
water level.

Lake Biwa Water LevelTimein 1905 had to be replaced with a new, mechanicallycontrolled weir in 1961. The new, precision-control weirwould now be fully closed and fully opened in just 30 min.

Relationship Between Seta River
Dredging and Weir
The dredging of the Seta River and operation of the weir are
inextricably linked. The weir controls the Lake Biwa waterlevel in such a way that, under predicted heavy rains, thelake level may be reduced to lower than the normal level
and, in turn, the dredged river bottom at the lake outlet
would allow ﬂooding water stored in the lake to be quickly
released when the downstream ﬂooding risk has been sufﬁciently reduced. Dredging alone, however, would pose theproblem of causing the lake water level to decrease too muchat times when there is little rain. The weir prevents this fromhappening by holding back the water and allowing the lake
to function as a reservoir for downstream water uses. The
dredged channel, in turn, allows passage of the amount ofwater required by the downstream, as regulated by the weir.

Synchronizing Weir Operation with HydraulicBehavior of Yodo River and Lake Biwa
Under conditions of heavy rains, the peak discharge from
Lake Biwa can be controlled, whereas the Lake Biwa reaches
its peak water level more slowly (approximately one day)than the peak ﬂow in the Yodo River, because of the

topographic and hydraulic characteristics of the upstream
Biwa Lake and the downstream Yodo River catchment area.
This results in a “time lag” between the impacts of heavy
rains on Lake Biwa versus the Yodo River (>Fig. 5). Thislag is actually beneﬁcial for managing the Yodo Riverﬂooding. When there is heavy rain, the Lake Biwa discharge
may be restricted or completely shut oﬀ. Once the downstream ﬂow starts to subside, the weir operation may be
synchronized to allow discharge of lake water, thereby
allowing the lake water level to slowly decrease (>Fig. 6).
Applying this principle, the weir may be operated in such a
way that dredging would not increase the risk of downstream ﬂooding. When it rains, the rise in water level canbe kept within certain bounds, such that the duration ofpeak water level may be promptly reduced.

Conflicts over Fully Closing Seta River Weir
Before the Seta River Weir was installed, people living
downstream strongly opposed dredging of the outﬂow
channel, arguing that Lake Biwa was a self-regulating natural lake. They believed that increasing the ﬂow capacity
would upset the lake’s natural equilibrium. Once the weir
was installed, however, it became possible to carry out
large-scale dredging of the Seta River. The increase in the
discharge capacity of the Seta River allowed lowering of
the Lake Biwa water level at times of ﬂoods, therefore,
reducing the ﬂooding damages around the lake. However,
the weir would have to be kept fully closed to prevent lakewater passing down to the Yodo River at times when it isEvolving History of Lake Biwa and Yodo River Basin Management

6⊡ Fig. 6
Synchronized weir operations.

already on the verge of ﬂooding with waters coming fromthe Katsura River and Kizu River watersheds. Thus, what is
beneﬁcial for upstream, that is, opening the weir at timesof ﬂooding, is not likely to be beneﬁcial for downstream
residents, being the fundamental cause for the upstream–
downstream conﬂict.
For example, in 1917, when a restoration work was being
carried out in the wake of ﬂooding cause by a broken
embankment downstream at Otsuka (at the western bank of
the Yodo River across the city center of Hirakata City today),the citizens of Osaka and Shiga Prefectures submitted apetition against the dredging, and a counter-petition in favorof the dredging, respectively, to the central government. The
dispute only subsided when the Emperor visited to inspect
the completed work. As another example, in the ﬂood seasonof 1972, the Shiga Prefecture strongly opposed keeping theweir fully closed, by strongly protesting to the central government. Similarly, in 2006, the Shiga Governor made an urgent
request to the central government to, as far as possible, avoid
completely closing the weir. To date, the weir operation policy
at times of ﬂooding has remained a major issue of contention
between upstream and the downstream interests.

6.2.4 From the LBCDP Era to the Present
Having turned out to be a 25-year plan (1972–1997),
rather than the originally anticipated 10-year plan
(1992–1981), LBCDP has expended 1.9 trillion Japanese

Yen. The broader goal of the project was set at developing
and managing Lake Biwa in order to contribute to thesound development of the Kinki Region and to thewell-being of everyone who relies on the lake.
Specifically, the objective of LBCDP was to make properand effective use of Lake Biwa’s resources, while conserving the lake and its surroundings, improving thequality of polluted lake water, and protecting the naturalenvironment.
The policies of the project were guided by three mainconcerns.
•••

Management of Lake Biwa water quantity to further
reduce ﬂooding around the lake
Development of the water resources for downstream
users, as well as for Shiga Prefecture
Improvement of Lake Biwa water quality and conservation of the natural environment

Practical targets included development of water
resources for the downstream use amounting to a maximum
40 m3/s at times of droughts, construction of Lakeshore
embankment for ﬂood control around the lake, and dredging of the Seta River, together with installation of pumping stations to drain the inundated ﬁelds. Under the local
development projects, including road construction, sewerage installation, establishment of nature conservationparks, solid waste disposal facilities, water quality monitoring stations, and irrigation return ﬂow pollution treatment facilities were to be implemented by Shiga Prefecture

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Evolving History of Lake Biwa and Yodo River Basin Management

and the Water Resource Development Corporation, withﬁnancial support coming from the national as well as thedownstream prefectural and municipal governments,
apart from the due payment to be made by the Shiga
Prefecture itself.

Planned Management of Lake
Biwa Water Level
The purpose of LBCDP was to fulﬁll the water supply
needs of the downstream Keihanshin (the general designation of the greater metropolitan region encompassing
Kyoto, Osaka, and Kobe metropolitan regions), based on
the arrangement to release the Lake Biwa water down
through the Seta River Weir (at a maximum of 40 m3/s
during extreme droughts), as well as coping with the ﬂoods
of a scale that may occur once in 100 years (a 100-yearﬂood). Consequently, the maximum draw down level oflake water was set at −1.5 m (1.5 m below B.S.L.). In addition, a special arrangement was made for the Shiga
Prefectural residents that any damages incurred due to thewater level decline between −1.5 m and −2.0 m would becompensated by the national government and downstream
local governments. The agreed process is that the contingency plan would be implemented for the domestic, industrial, and agricultural waterworks to continue to function
when the lake water level declines toward −2 m, and thatthe compensatory payments would be made for wells that
may run dry. Other provisions include compensation to
the ﬁsheries to oﬀset income losses related to reduced ﬁshcatches. On matters pertaining to the maximum waterlevel, the planned high water level is set at 1.4 m above
B.S.L. to cope with the 100-year ﬂoods, in conjunction
with other countermeasures carried out around the lake.
Thus, the Lake Biwa water level is controlled in the rangeof −1.5 m and +1.4 m as per B.S.L.
The Lake Biwa Flood Protection Plan was drawn up
after considering the ﬂood protection and water supply
needs of the Yodo River system as a whole. There are threemain strategies, including the following: (a) reducing thewater volume in the lake during seasons prone to ﬂood
damages; (b) dredging the Seta River; and (c) other works,
including embanking around the lake shore, sluice gates,and pumping stations to remove water from the ﬂooded
land. These strategies are elaborated as follows:(a) Reducing ﬂood season lake water levels: During theﬂood seasons, the lake water level would be reduced inadvance to prevent lake overﬂow and consequentﬂooding of land near the lake. Depending on the

period, the lake would be reduced to –0.20 m or –0.30
m. The lake was previously maintained at B.S.L. ±0;(b) Seta River dredging: With the greater discharge capacity resulting from dredging of the Seta River, the swollen lake water volume, with the increased water level,
could be reduced relatively quickly. The plan calls speciﬁcally for dredging to increase the discharge capacityfrom 600 m3/s to 800 m3/s, as measured at B.S.L. ±0 m.
(c) Peripheral ﬂooding countermeasures. To prevent ﬂooding of low-lying lands when the lake level rises, thesluice gates were installed on the feeder river channels:
Construction of lakeshore embankment (>Fig. 8)
and sluices to a crest height B.S.L. +2.6 m, with aplanned high water level of B.S.L. +1.4 m.
Pumping stations to remove ﬂood waters, including
14 facilities in six vulnerable areas. There also was an
improvement of inﬂowing channels involving 13 rivers(>Fig. 9).

Setting Flood Season Lake Water Level Limit
While water in the lake was previously maintained at B.S.L.
±0, the level is now set as B.S.L. –0.20 m from June 16 toAugust 31 and, from September 1 to October 15 at –0.30
m. This is intended both to reduce the time that the lakewater level is higher than normal and to shorten the ﬂooding period.

Seta River Dredging
The Seta River, the only outﬂow channel from Lake Biwa,
was excavated to increase the lake water discharge rate.
The increased discharge allows for lowering of the lakelevel in anticipation of increased rainy season waterinﬂows. This “prelowering” of the water level also would
allow the lake to accommodate the 100-year ﬂoods, withthe lake level reaching its high water mark of B.S.L. +1.4 m.
Further, the increased discharge capacity of the lake will
enable the prompt reduction of its water level, which
would lessen the potential ﬂooding damages around thelake peripheries (>Fig. 8).

Shoreline Flood Management Measures
Prevention of overﬂow from the lake, and removal of inundating water, was one of the major goals in the Lake Biwa
Comprehensive Development Project. Consequently, theconstruction of the lakeshore embankment and the riverEvolving History of Lake Biwa and Yodo River Basin Management

channel improvements were key elements. To allow for 1.2
m headroom over the B.S.L. +1.4 m planned high waterlevel, the levy embankment was constructed up to the heightof B.S.L. +2.6 m around the lake. Channel improvement of
inﬂowing rivers also was carried out, and the pumping stations were installed to remove water that might spill overfrom ﬂooded rivers to cause lowland inundation aroundthe lake that was blocked by the levy structure.

Formulation of Weir Operating Principles
Even after the weir was installed, regulations for its operation were still undecided because of continuing opposing
upstream and downstream interests. As LBCDP neared
completion in 1992, however, upstream and downstream
agreement had been achieved, and the operating regulations decided. At the same time, downstream water users
in Hyogo and Osaka Prefectures were ﬁnally able to execute their acquired right to draw up to 40 m3/s of waterfrom the Yodo River during times of severe droughts. The
Seta River Weir has been managed and operated based onthese regulations since April 1, 1992.
Under these regulations, the planned peak water level is
set at B.S.L. +1.4 m. Seasonally, during the potential ﬂood
periods, the level is reduced to B.S.L. –20 cm or –30 cm(between June 16 and October 15), while at other times,
when there is a low risk of ﬂooding, the water level may be⊡ Fig. 7
Water level adjustment
in Lake Biwa.

6

allowed to reach B.S.L. +30 cm (between October 16 andJune 15 the next year). Accordingly, water discharges
through the weir are ﬁnely controlled to not exceed theregulated values. During times of downstream water shortages, the Weir would be ﬁnely controlled. If the Lake Biwa
water level decreases to below B.S.L. –1.5 m, however,
Ministry of Construction (redesignated as the Ministry ofLand, Infrastructure, Transport, and Tourism since 2001)
decides the weir operation policy, after consulting with theGovernor of Shiga and the other prefectures concerned(>Fig. 7).

Yodo River Improvement Master Plan
(1971–2007): Management of Entire
River System
The Rivers Act of 1896 was revised in 1964 to promote theintegrated management of both ﬂood control and watersupply in the entire drainage systems. Based on the revised
Act, the ﬁrst Yodo River Improvement Master Plan wasdeveloped in 1965, covering the entire Yodo River andLake Biwa. Recognizing the need for security for theincreased population and the expanded industrial areas in
the Yodo River basin against ﬂooding, this plan had to becompletely overhauled. It was eventually implemented in1971 with the goal of preventing the damages even fromthe 200-year ﬂoods. As of 2010, based on the work carried

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6

Evolving History of Lake Biwa and Yodo River Basin Management⊡ Fig. 8
Lakeshore embankment.

out under the plan, the objective of ﬂood control is toprevent the 200-year ﬂoods at speciﬁc downstream reference points.

Fundamental Yodo River Management
Policy and Yodo River Improvement Plan
(2007–Present)
In addition to the concern hitherto restricted to ﬂood control and water resource development, the 1964 Rivers Act
was further revised in 1997, with the goal of dealing withrehabilitation and protection of the river environment.
In conformity to this revised Act, the Fundamental
Yodo River Management Policy was formulated in August
2007, from which the Yodo River Improvement Plan wasdeveloped in 2009. The spirit of the Policy was, “rather
than sacriﬁcing one area of a region to protect another, theintention is to improve security from ﬂooding in the entire
river basin; and after the downstream ﬂood control infrastructure development has been completed and as long as
there would be no threat of ﬂooding downstream, the Weirwould not be completely closed.”
Since the end of the nineteenth century, the fundamental concept of the Yodo River ﬂood control was tolower the normal Lake Biwa water level in advance to oﬀset ﬂood season high water levels. The integrated ﬂood
management policy has consistently combined thisprelowering before the seasonal inﬂow of water withdredging of the Seta River to increase the lake outﬂow
capacity, and closing of the Seta River Weir to reduce
downstream ﬂood risks.

6.3 Water Resource Developmentin Lake Biwa Region
6.3.1 Overview
As was typically the case throughout Japan, the earlymotivation for water resource development in the BiwaYodo Basin was the water need for paddy irrigation. The
lake region remained poor, sustaining their livelihood
more or less exclusively on the basis of a rural agricultural
economy. Despite its large quantity and close proximity,
Lake Biwa water was not a viable water resource option
for the riparian communities in the days when electricity
was still not widely available for pumping water upland.
Rather, the lake watershed communities had to resort tothe diversion of the unstable feeder river waters for paddy
irrigation and for meeting their daily needs. During the
droughts, the upstream farmers would divert almost all of
the river water, leaving little for the downstream users.
While the upstream water users usually have the power tocontrol the water, they also have to ensure the water use
conﬂict with the riparian communities would eventually

Evolving History of Lake Biwa and Yodo River Basin Management

6⊡ Fig. 9
Pumping stations andInundation area around
Lake Biwa.

be amicably resolved, by means of various sophisticatednonstructural measures for conﬂict resolution. One such
example is the formation of water user associations foreﬀective and equitable water distribution. Another example was uniﬁcation of the individual diversion intakes insuch a way there would be only one water user association
along the same diverting river system. This irrigationwater use culture evolved over the period of more than
300 years.

Unfortunately, however, even with such measures, theresolution of water use conﬂicts was always diﬃcult.
Speciﬁcally in the Lake Biwa region, the unique geo-topological and climatic conditions made paddy irrigation particularly problematic. Simply stated, frequently too little or
too much water was available in many parts of the basin.
In old days, the structural measures were limited to constructing impoundment ponds and/or earthen barrages tohelp ameliorate such hardships.

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Evolving History of Lake Biwa and Yodo River Basin Management

6.3.2 Water Needs and Management
Challenges
On the other hand, the communities in the downstream
Yodo River have had access to the water, mainly that originating from Lake Biwa, at many water intake locations.
The stable water-abundant communities have grown overtime to become today’s Keihanshin economic region, witha high concentration of industries and populations. In
addition, at times of heavy rain over the lake watershed,
the ﬂood control weir constructed at the discharging
mouth of the lake was operated on the principle requiring
the ﬂood waters to be kept within the lake basin. The overall political and economic dynamics remained skewed infavor of the downstream interests over the upstream interests. However, by 1950s and 1960s, the structural measures
included construction of large scale, multiple-purpose
dams, together with installation of large-scale pumping
stations for distribution of the abstracted water throughthe irrigation pipeline networks. The conjunctive use ofriver and lake waters was realized for the ﬁrst time during
LBCDP for ﬂood protection and land development of theriparian lowland communities, and for generating additional water rights for irrigation, although its primary purpose was to allow more water to be made available to thedownstream region during times of extreme droughts. The
additional water rights and the traditional rights had to beproperly realigned for equitable allocation.
The era of water resources development has lasted for
decades, and by the mid-1990s, the projected severe water
shortage for the urban and industrial sectors in the 1960s
and 1970s seem to have been signiﬁcantly moderated withthe completion of a suﬃcient number of dams and reservoirs across Japan. By then, however, the negative impacts tothe environment and nature by these hydraulic structures
also have grown to become a major contentious issue inmany parts of Japan, including in the Biwa-Yodo Basin. The
growing concern for the environment and for the wastefuluses of the supplied water made the conventional approachof supply-side water management outdated. There is strong
sentiment on the need for a paradigm shift from the supplyside water management to demand-side management.

6.3.3 Low Flow Regulation:
Some Dictating Facts
As discussed in previous sections, management of Lake
Biwa water, speciﬁcally its water level, has historically beenhighly contentious and conﬂicting, particularly withrespect to supplies of water, and control of ﬂoods. Thoseliving in the downstream Yodo River want Lake Biwa
water to be kept within the lake during times of ﬂoods,
and for water to be released downstream during drought
periods. Combined with the fact that the demand for Lake
Biwa water in the downstream Keihanshin Region has
been predominantly for urban and industrial uses, whilethat in the upstream Lake Biwa region has been dominantly for agricultural use, there are some dictating facts
about the ways with which a variety of policy tools has
historically been introduced.

The Hirakata Gauging Station
The water quantities required under the water rights forsatisfying the thirst of the downstream Yodo River are
allocated at Takahama, immediately upstream of the
Hirakata conﬂuence point of Uji, Katsura and Kizu Rivers(see >Fig. 1). At the Hirakata Gauging Station, the low
ﬂow regulation is set at 186.51 m3/s during the irrigationseason (May 1 to October 15) and at 169.71 m3/s in thenonirrigation season. Of these water ﬂows, the minimum
requirement for environment protection and naturepreservation is set at 85 m3/s, which consists of 70 m3/s
allocated to the Oh River (Oh-kawa), 10 m3/s allocated to
the Kanzaki River (Kanzaki-gawa), and 5 m3/s to passthrough the Yodo River Big Weir (Yodogawa-Ohzeki).
The quantities of water allocated for agricultural use is
16.8 m3/s, and for industrial and municipal uses together
is 101.51 m3/s.

Ascription of Water Rights
Around 70% of the total water discharge at Hirakata comesfrom the Uji River, which originates from Lake Biwa.
During the dry season, the daily releases from Lake Biwa
are approximately eleven million m3 (130 m3/s) which corresponding to about 1.6 cm of Lake Biwa depth (1 cm ofdepth from surface corresponds to about 6.8 billion m3).
Based on the Yodo River Water Resources Development
Master Plan (or the Yodo River Full Plan, described indetail in Section 6.3.4), 40 m3/s was ascribed to the waterlevel control of Lake Biwa through LBCDP, 15.175 m3/s tothe ﬁrst stage Yodo River improvement works, 15.576 m3/s
to the natural base ﬂow, and the remaining ﬂow to various
dams (Takayama, Hinachi, Shourenji and Hiyoshi Dams),
and other water control measures (Yodogawa Ozeki Weirand Shorenji Water Intake).

Evolving History of Lake Biwa and Yodo River Basin Management

6⊡ Fig. 10
Torii River Gauging Station and Seta River Weir.

6.3.4 Key Water Resource
Development Issues

Construction of Kyoto Canals and First Stage
Yodo River Improvement Works

Seta River Weir and Torii River
Gauging Station (>Fig. 10)

Prior to industrial development in the late-nineteenth
century, the use of Lake Biwa water was limited to small
scale drinking water supplies, paddy irrigation in the lowlying lands, ﬁsheries, and navigation. At the dawn of the
Meiji Restoration Period (1868–1912), however, the government was intent on developing industries, resulting ina critical need for hydropower generation and water
resources. Notable in that respect were two major Lake
Biwa projects. The ﬁrst was construction of Lake Biwa
Canals, and the other was the First Stage Yodo River
Improvement Works. The Lake Biwa Canals were constructed between 1885 and 1912. Completed in 1890, theFirst Canal, with a capacity of 8.35 m3/s, was designed tomeet the navigation, hydraulic works, and irrigation needs.
Completed in 1912, the Second Canal, with a capacity of
15.3 m3/s, was designed to meet water supply and hydropower needs. The total design capacities of the two canals
amounts to 23.65 m3/s, being managed by the City of
Kyoto for drinking water (12.96 m3/s), industrial water(0.004 m3/s), irrigation water (1.12 m3/s), and other uses
(0.781 m3/s). The hydropower station constructed at Keageat the outlet of the Second Canal was the ﬁrst such system
in Japan and, together with the hydropower dams constructed in Uji River and Shizu River downstream of Lake
Biwa, gave the lake an important role in energy production. (See also Topics 21)
The First Stage Yodo River Improvement Works wasundertaken mainly to support the war footing in 1943

The water level of Lake Biwa, as related to drought andﬂood management, has always been the focal issue ofcontention between the upstream and downstream stakeholders. When the Nango Weir was completed in 1905, thebaseline elevation of the Lake Biwa water surface, as measured at the Torii River Gauging Station, was determined tobe 85.671 m against the Osaka Pail (or the standard seawaterlevel of Osaka Bay). Thereafter, all construction works andwater management decisions refer to this B.S.L. as the standard water level of Lake Biwa (Biwako Stand Level, or B.S.L.
± 0 m level). As an aside, this B.S.L. formed the baseline fordetermining various design parameter values comprising
the structural and nonstructural interventions stipulated in
LBCDP, including the planned high water level of +1.4 m(of which the free board height is +1.2 m), the planned
Lake Biwa water levels during summer months (−0.2 m
from June 16 through August 31, and −30 cm from
September 1 through October 15), the maximum waterlevel under normal weather conditions of +0.3 m, theusable water drawdown of −1.5 m, and the damage compensation water level of −2.0 m. In other words, the lakelevel has been meticulously controlled to make Lake Biwa
function both as a ﬂood control dam, and as a water supply
reservoir, depending on the seasons and the prevailing precipitation phenomena at the time (>Fig. 11).

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Evolving History of Lake Biwa and Yodo River Basin Management⊡ Fig. 11
Lake Biwa Canal inlet and open channel.

during the Second World War. Some 120 m3/s of Lake
Biwa water was to be supplied to industries, to drinking
water supply, and to hydropower generation, for which theLake Biwa water level was lowered down to −1.0 m B.S.L.
by dredging the Seta River and realigning the Daido River
conﬂuence to the Seta River. The project was only partiallycompleted in 1947 because of the ending of the war in
1945, was later succeeded by the Yodo River Water
Resources Development Master Plan (the Yodo River FullPlan) of 1962, being ﬁnally completed through LBCDP in
1997 with modiﬁcations (see Section 6.4 for details).

Yodo River Water Resources Development
Master Plan (Yodo River Full Plan)
To support rapid urbanization and industrialization after
Second World War, the national government was intent on
developing hydropower generation, urban and industrial
water supplies, and irrigation systems. The Law Pertaining
to Construction of Multipurpose Dams was enacted in1957 to discourage wasteful investments in river management. In 1961, the Law for Promotion of Water Resources
Development and the related laws were enacted to acceleratewater resource development, with a provision to identify
seven priority river systems to receive funds for integrated
development. The Yodo River was included as one of theseven systems, enabling the development of the Yodo River
Master Plan (also referred to as the Full Plan) for water
resource development. The Full Plan acknowledged thewater rights generated, respectively, by LBCDP (40 m3/s),
Takayama Dam (5 m3/s), Shorenji Dam (2.49 m3/s),
Murom Dam (1.6 m3/s), Hitokura Dam (2.5 m3/s), Hiyoshi
Dam (3.7 m3/s), Hinachi Dam (1.5 m3/s), and Nunome
Dam (1.14 m3/s). In 1964, the River Law of 1896 wasrevised, with the new stipulation for water rights and otherrelevant issues. Based on the Full Plan as a long-term water
resources development plan, many water resources, irrigation, and river engineering construction projects were
gradually undertaken over the following years.

6.3.5 Developing the Lake Biwa
Comprehensive Development Plan
Soon after Second World War, and recognizing the need fora long-term, comprehensive resource development projectfor Lake Biwa, the Lake Biwa Comprehensive Development

Evolving History of Lake Biwa and Yodo River Basin Management

Council was inaugurated in 1952. The Council members
consisted of three groups, that is, the national government,
three downstream prefectural governments, and the majorwater user associations. In addition, the Shiga Prefectural
government, the reluctant but only upstream stakeholder,
was also a member. The main objectives for establishing theCouncil was to reach an agreement for the downstream
users, mainly the Osaka and Hyogo Prefectural governments, to have access to greater quantity of Lake Biwa water.
The contention of the Shiga Prefecture was that the ﬁrst priority should be to fulﬁll the local community needs, and todevelop the infrastructure for local and regional economic
development, with provisions for nature conservation andenvironmental protection.
The Council members elaborated on the assessment of
the visible/invisible and/or tangible/intangible values, andon the responsible bodies for taking care of such values.
Although the Minister of the Construction had the legal
right to decide on the fate of the Lake Biwa water, it would
not be possible to decide on the fate of the Lake Biwa water
without having the agreement of the Shiga Prefectural
government to the terms of the proposed plans and programs. Eventually, the downstream Osaka and the National
Government accepted the view expressed by Shiga Prefecture that water resource development for the downstream
should be accompanied with regional economic development of the upstream Lake Biwa region. Thus, the scope of
the water resources infrastructure development projects
stipulated under the Full Plan was expanded and, together
with ﬂood control and environmental amenity projects,
the Full Plan was transformed into LBCDP of 1972.
It is important to note here that the water resourcescomponent of LBCDP involved intricate political settlements among the key stakeholders. The downstream residents insisted the planned drawdown of the lake waterlevel should be −2.0 m, corresponding to 40 m3/s of additional lake water discharge, as per the engineering computations performed by the Ministry of Consturction,
reorganized into the Ministry of Land, Infrastructure,
Transportation and Tourism in 2001. The Shiga Prefectural
Government, on the other hand, considered the ﬁguresunacceptable, and insisted on the discharge to be 30m3/s,
corresponding to −1.5m of drawdown. The two were instrong disagreement, seemingly jeopardizing the conceptual basis of LBCDP. In March 1972, however, the Ministerof Construction and the four Governors met and agreed
to the Statement of an Exchange of Promises (Moushiawase
in Japanese) stipulating:
1. The quantity of additional discharge from Lake Biwa
at times of extreme droughts is agreed to be 40 m3/s.
2. The maximum drawdown should be B.S.L.−1.5 m.

6

3. The Minister of Construction will honor the opinionsof the prefectural Governors before making the ﬁnal
decision on the operation of the Seta River Weir during times of extreme drought.
The Statement in eﬀect adopted the politically compromised ﬁgures of 40m3/s and −1.5m, and, although thecompensatory engineering works to be performed for thein-lake facilities to the drawdown level down to −2.0m,
rather than just to −1.5m was not included in the Statement.
Being inconsistent against the results of technical analyses,
this political settlement later became a focal issue of
discussion on the need for new Weir operational rules formeeting environmental and ecological needs. In otherwords, the Statement in a way reﬂects the implied societal
consent to let political tensions supersede technicalintegrity. Having the regional economic development andthe environmental enhancement project components
added to the water supply and ﬂood control components,
the total budget of LBCDP eventually exceeded 1.9 trillion
yen. The project, which was originally designed to be oneof water resources development, was realized through an
extremely intricate political compromise.

6.3.6 Irrigation Improvement Projects
in Lake Biwa Surroundings
An extensive part of the lowland area of the Lake Biwa
watershed is irrigated for paddy agriculture. The irrigation
systems prior to LBCDP were typically limited to cascading of stream waters from the upstream impoundments
and barrages. The Shiga farmers were keen to have thesesystems improved through LBCDP, and various irrigation
improvement projects were undertaken with ﬁnancial
support from it. Three categories of the irrigation improvement programs were developed: (a) construction of newlake-water irrigation facilities to compensate for the lowered groundwater level; (b) regional economic development program; and (c) environmental enhancement
program. The lake-water irrigation program had two components. One was construction of large-scale pumping
stations and water distribution pipelines, and another wasconstruction of the irrigation return ﬂow recirculation
systems. The regional economic development program
involved farmland consolidation projects with improvement of irrigation and drainage canals/ditches and farmroads. The environmental enhancement program included
development of rural wastewater systems. Described
below are some typical cases of each of the three programs(>Fig. 12).

389

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6

Evolving History of Lake Biwa and Yodo River Basin Management⊡ Fig. 12
Ecologically soundirrigation return-flow
drain.

Irrigation by Pumping of Lake Water
Today, some 30% of the total farmland of Shiga Prefecture,comprising about 24,000 hectares, is supplied with pumped
Lake Biwa water. In addition, about 14% is supplied withriver water mixed with lake water. The lands provided withthese new irrigation systems used to be those least favorable for paddy agriculture for two reasons. First, they werelocated quite a distance away from stream water sources,
and second, they were located in the low-lying areas prone
to inundation (>Fig. 13).

Recirculation of Irrigation Return FlowsThe concentrations of organic substances measured as
COD, and nutrients measured as Total Nitrogen (TN),have been increasing in Lake Biwa over the past decades.
The irrigation return ﬂows are regarded to have been
partly responsible for the increases. The percentage contribution of agricultural nonpoint-source pollution loads are
13% for COD and 15.4% for TN, slightly less than thosefrom the industrial point source pollution loads, exceptthat pollution load reductions from nonpoint sources ofpollution are much more diﬃcult to address. The policy
measures introduced in Shiga Prefecture include the recirculation of polluted irrigation return ﬂows. The system,
consisting of irrigation return ﬂow collection reticulation

networks combined with a pumping station attached to areturn-ﬂow collecting pond, is designed to minimize thedischarge of pollutants into the lake. In addition, some ofthe drainage canals are recently being replaced with canals
composed of gravels and ﬁlter materials supplemented
with aquatic plants to reduce COD by oxidation and biochemical decomposition processes.
The irrigation return ﬂows are also problematic, however, because of the so-called “irrigation mud-waters,”
generated during the paddling-planting and transplanting seasons. They contain high concentrations of suspended solids, and can result in serious negative impacts
on the lake ecosystem. The recirculation of irrigation
return ﬂows is expected to signiﬁcantly reduce the concentration of suspended solids. As of 2008, some 25% of
the total 7 million m3 agricultural return ﬂow is subjected
to recirculation. Introduced below are pilot project caseson the Hino River integrated irrigation development
project and on the Akanoi Bay water quality conservation project.

Project Case 1: Hino River Integrated
Irrigation Development Project
The Hino River basin stretches out from the central highland region of the eastern watershed of Lake Biwa. Within
this basin, LBCDP provided for 110 diversion structures,

Evolving History of Lake Biwa and Yodo River Basin Management

6⊡ Fig. 13
Irrigation return flow circulation system.

150 farm ponds, 120 pumping stations for groundwater
extraction and distribution, as well as for supplying water
to the former wetland reclaimed as “polder” farmland. The
operation and maintenance of these facilities were carriedout individually by many small irrigation associations.
Many of the inherent water use conﬂicts had to be resolved
through individual agreements between, and among, thewater user associations (>Fig. 14).
Speciﬁcally, the Project, initiated in 1985, consists ofconstruction of the Zao Dam in the upper reach of the
Hino River, and a large scale lake-water pumping station
with a 4-level boaster pump system to lift the lake water up
to the elevation of 220 m. The water intake structure of thepumping station is located some 420 m into the lake to beable to withdraw water even when the lake level drawdown
reached the compensation maximum of −2.0m. The maximum quantity of lake water withdrawn is 7.3 m3/s, the lifting elevation is 60 m, and paddy area coverage is 3,000 ha.
Together with the river water captured in the Zao Dam, a
total land area of 5,210 ha is irrigated with this system. The
lakeshore paddy lands, which used to be prone to inundation, were improved by the drainage network systems
equipped with draining pumps. Working conditions andwork productivity have been remarkably improved
through this project. These newly constructed irrigation
systems, however, are not free of problems. The complex
maze of creeks containing rich biodiversity has been lost,
and the lake-river-paddy linkages have been shuttered forthe sake of converting the wetland paddy system to the
dry-land irrigation paddy system. There is now the challenge of restoring some of the lost ecosystem properties.

Project Case 2: The “Whirligig Beetles –Mizusumashi – Plan” in the Akanoi Bay
The Akanoi Bay is a small embayment in the South Lake andone of the most polluted parts of Lake Biwa from urban
and agricultural nonpoint-source pollutions, together withthe pollution from domestic and industrial wastewatereﬄuents. It has been experiencing occasional blooms of
blue-green algae, and the Shiga Prefectural government hasgiven a high priority to its restoration. The plan is called the“Whirligig beetle – mizusumashi – Plan.” (>Fig. 15)
Whirligig beetle, or “mizusumashi” in Japanese, is a
freshwater insect known to feed on aquatic organic debris

391

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6

Evolving History of Lake Biwa and Yodo River Basin Management⊡ Fig. 14
Hino River project overview map (Source: Shiga Prefecture).

and planktonic matters, thus contributing to purifying thewater in which they thrive. All of the Shiga Prefecture projects for purifying the agricultural return ﬂow are collectively
dubbed as the “Whirligig beetle, or mizusumashi, Plan”.
The project consists of several engineering components, that is, construction of an oxidation ditch, introduction of aquatic plants for water puriﬁcation, recirculation
by pumping of agricultural return ﬂows, and reconstruction of diversion structures, with a total expenditure of
1.63 billion Japanese Yen. According to the projected
achievement, the target reduction of COD is from 199.0 to
85.0, of TN from 67.2 to 37.6, and of TP from 6.3 to 2.43
(all expressed in g/ha/day). At the same time, the plan aims
at restoration of aquatic ecosystem health through citizen
participation and environmental education.

6.3.7 Water Use Changes in Urban
and Industrial Areas
Social Characteristics of Lake
Biwa Catchment Area
⊡ Fig. 15
Location of the Akanoi Bay Project (Source: Shiga Prefecture).

Japan’s population began declining in 2005. Together withthe trends of falling birthrate and aging population alreadyevident in the 1990s, Japan is ahead of other industrializedEvolving History of Lake Biwa and Yodo River Basin Management

nations in simultaneously experiencing these three trends.
In contrast to these national trends, however, Shiga
Prefecture is one of the few prefectures in the country
where the population continues to grow. The prefecture’s
population aging rate is also among the lowest in the
country. This is one of the key features characterizing
water use patterns in the Lake Biwa region.
The population of Shiga Prefecture declined after theSecond World War, reaching its lowest number of 830,000
in 1963. At that time, people and industries were moving
into Osaka City, the center of the Keihanshin Area, withthe city seeing its population grow to the postwar peak ofover 3 million in 1965. The concentration of populationand industries in Osaka City was a reason for the population decline in Shiga Prefecture.
Between the mid- and late-1960s, the Osaka metropolitan area expanded in size, resulting in a population decline
in Osaka City, with an increased population in the periphery of the metropolitan area. The population of Shiga
Prefecture, after reaching its lowest level in 1963, started
growing again, and has since been increasing for nearly 50
years. The growth has been particularly signiﬁcant along
the Japan Railway Lake Biwa Line between the Konan(south of the lake) District where Otsu City (Prefecture’s
capital) is situated, and Koto (east of the lake) District.

Industrial Development in Lake Biwa Region
The locational pattern of industrial establishments in Shiga
Prefecture has been greatly inﬂuenced by the population
growth in the prefecture. Industrialization of Shiga
Prefecture was triggered by the establishment in the late1910s of textile industries such as sericulture, cotton
spinning, and rayon productions. It resulted as one of therippling eﬀects of the development of industries after FirstWorld War. The accumulation of the rayon industry in
Otsu City was particularly signiﬁcant, raising the country’s
rayon output to be the world’s number one producer before
Second World War. Despite such industrial developments
before Second World War, however, Shiga Prefecture wasstill seen as an agricultural prefecture because of its limited
number of industrial activities. It was between the 1960s
and early 1970s—the high growth period—that this characteristic fundamentally changed, with the prefecture
starting to shift toward an industrial prefecture.
The industrial growth of Shiga Prefecture has much to
do with the development of regional transportation systems. At the time of the ﬁrst peak of industrial accumulation around 1960, the National Artery Road No. 1 waspassed through the prefecture, soon to be followed by the
National Artery Road No. 8. With the opening of the Shiga

6

portion of the Meishin (Nagoya-Osaka) Expressway in
1964, together with the completion of the Biwako Ohashi
Bridge connecting the National Artery Road No. 8 to the
Kosei (west of the lake) District’s National Road No. 161,
the main transportation routes of the prefecture werefairly well-established. As a result, the Shiga Prefecture wasconnected not only to the Keihanshin Area through thenational Artery roads, but also to the Tokai and Kanto
areas through the national expressways.
It was in the early 1970s when the textile industry, oncethe pillar of the prefecture’s industries, decreased its share of
the prefectural industrial output, being replaced by electricand general-machinery industries. For nearly 40 years sincethen, these electronic and general-machinery industries,
together with many diﬀerent types of assembly industries,
have characterized the industrial proﬁle of the prefecture.

Relocation of Industries from Outside
Shiga Prefecture
For the textile industry, established in Shiga Prefecture
before the Second World War, Lake Biwa was a major
attracting factor. Being constrained by the limited transportation access to the Japan National Railway system(now the Japan Railways) and a small number of regionalroads, these industries were mostly conﬁned to the lakeshore area.
On the other hand, during and after the high growth
period, the development of road transportation networks
with access to the designated industrial lands were a determining factor for industries to be located in the lowland as
well as upland areas within Shiga Prefecture. In particular,
the Meishin Expressway, which runs through the higher
elevation along the foot of the surrounding mountains,
allowed industries also to be located in high altitude areas
with access to the connecting local roads. The establishment of industrial parks was an additional factor. Whenthe road network was signiﬁcantly improved in the early
1960s, some 59 industrial parks were constructed, including those in Omihachiman, Konankogyo, Kusatsujutaku,
and Minakuchijutaku. The industrial complexes were initially developed in the lowland ﬂat areas, but gradually
spread to areas away from the lakeshore. Many of the largescale complexes today are located in hilly areas, contributing to the concentration of industries in upland areas.

Industrial Water Use Characteristics
Many of the industries established in the prefecture, during and after the high economic growth period, were not

393

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Evolving History of Lake Biwa and Yodo River Basin Management

250.0
Total
Recycled water
Supplied water
Well water
200.0

Surface andSubsurface waters
Industrial watersupply⊡ Fig. 16
Industrial water use in
Shiga Prefecture bysource (Supplied
water + Recycledwater = Total Industrial
water supply + Surface
and Subsurface
waters + Wellwater = Supplied water).

150.0

100.0

50.0

0.0
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008

394

dependent on the availability of water. Thus, the availability of local water sources was not a determining factor.
>Fig. 16 shows that the total quantity of freshwater use
increased 1.7-fold between 1980 and 1998 (the peak year).
The quantity then started declining and, in 2008, was at thelevel of 20 years ago. However, the fact that there was little
correlation between the total quantity of water used andthe quantity supplied, and that the quantity of water
recycled was correlated with the total quantity of water
used, suggests that the demands for industrial water could
be met by increasing the water recycling rate.

Historically, groundwater has been the major source ofwater for both agricultural and domestic purposes in Shiga
Prefecture. Much of the industrial water has also been
groundwater extracted from deep wells, and from subsurface inﬁltrations (nearly 75% in total). The dependency on
public water supplies has been quite low, with this trendchanging little since the 1980s. The diverse potential of a
local water resource is a unique feature of the Prefecture.
In summary, there is little direct relationship between the
proﬁle of the prefecture’s industries and the use of waterfrom Lake Biwa.

Evolving History of Lake Biwa and Yodo River Basin Management

Urbanization and Water Demands
After the late 1960s, Shiga Prefecture was caught in the wave
of urbanization and industrialization. Development of residential areas in the Konan and Koto Districts, as well as thegrowth of catering service industries to business establishments and general households has contributed to anincreased demand for domestic and urban water supply.
With a population of approximately 1.39 million, thewater supply coverage was 99.2% as of March 2007. The
maximum water supply per day per person was 488 liters, ahigh value. The makeup of water sources in Shiga Prefectureis lake water (69.7%), deep and shallow wells (23.4%), surface and inﬁltration water (6.5%), and spring and otherwaters (0.3%). In contrast, river waters are not used at all.
The dependency on groundwater, once a major feature ofwater use in the Lake Biwa catchment area, has been on the
decline, being less than a quarter in recent years. In contrast, the dependency on lake water is increasing.
The water source composition varies among regions.
In groundwater-rich regions such as the Koto Plain, houses
and business establishments have tended to use their private wells, thereby providing little incentive for the introduction of water supply facilities. This has also been thecase in the Kosei District. On the other hand, due to unstable groundwater supply and its low quality, the incentive
for setting up water supply facilities has been high in the
Konan and Koga Districts. Further, these areas also exhibited more industrialization and urbanization than otherareas of the prefecture, with a signiﬁcant increase in water
demands — a driving factor for development of water
resources.
In the 1960s, the Shiga Government began formulating a water supply development plan. In 1964, the pipedwater supply coverage in the prefecture was 42.3%, much
lower than the national average of 62.8%. This low coverage was due to the fact that people in most parts of theprefecture could use groundwater as a water source.
However, the Shiga government predicted this traditional
water-supply system would not be able to meet the prefecture’s future water demands if industrialization and urbanization continued in the future. During the period ofconceptualization of LBCDP in the late 1960s and early
1970s, it was predicted that implementation of the Project
would aﬀect the groundwater in the catchment area, causing problems for those depending on. In response, a plan
was evolved to shift the water supply source from groundwater to lake water. While cities adjoining Lake Biwa, suchas Otsu City, had already been using the lake water, it was
LBCDP that facilitated the gradual increase in the dependency on the lake water as a water source (see Section 6.4

6

for details). As a result, nearly 70% of the current watersupply is supplied by the lake.
Lake Biwa is also the ﬁnal destination of various types
of water discharged in the catchment area, as well as the
major source of water supply in Shiga Prefecture. The
Lake Biwa catchment area has formed a water demand
structure that cannot be seen in other areas. Therefore, thepeople who live in the catchment area invariably have to
pay extra attention to their water use and wastewater
discharge.

6.3.8 From Water Supply Management
to Water Demand Management
The Yodo River Water Resources Master Plan, as transformed into LBCDP, is a supply-based plan of water
management, meaning that new water demands would
have to be satisﬁed by the newly developed water source.
In other words, the new water users would have access tothe needed quantity of water resources by way of constructing water impoundment structures such as dams
and reservoirs, or in other ways for creating the additional water rights. The era of this supply-side water
management has long passed in Japan, where the needfor additional water has become more and more diﬃcult
to justify for the major water supply entities in the
Keihanshin area because of a declining water demand.
Further, the supply-based policy of water resource development resorting to dam construction in the past decades
has resulted in a supply of water that far exceeds thedemands. There is also strong sentiment against structural approaches of supply-based water management
because of the unavoidable negative impacts to the environment, and social disorders and conﬂicts. The call forchange in water resources management from that basedon supply, to that based on demand, seems to be a naturalchange in its paradigm.
The fulﬁllment of the new water demands can beachieved through: (a) transfer of existing water rights, (b)reorganization of water facilities such as dams and reservoirs, and (c) temporary transfer of water rights, collectively characterized as the water demand management
options. The Kinki Regional Bureau of the Ministry ofLand, Infrastructure and Transportation, Government ofJapan, has indicated the need for the following process inrealizing demand-based water management:
1. A thorough investigation of actual water uses anddemands
2. Revision of the water right system, particularly withregard to the ban in water right transfers

395

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6

Evolving History of Lake Biwa and Yodo River Basin Management

3. Reorganization of the water resource facilities
4. Restructuring of the drought coordination committee
Demand-based water management, combined with thepromotion of various water saving practices, should be sufﬁcient to provide for new water demands. The paradigm
shift from supply-based management to demand-based
management also means a shift from “construction” to“management,” complemented with nature conservationand environmental protection. Such a shift would be realized
only through wide-ranging participation of the stakeholder
organizations, including the general public. The hardcore
structuralism in the Ministry of Land, Infrastructure andTransportation (MLIT), however, is strong, in maintainingthat the prevailing climate change has been seriously aﬀecting the supply capacity of dams across Japan much lessthan the design capacity determined decades ago, cancelling the eﬀects of reduced demands.

6.4 LBCDP: Its Frameworks,
Accomplishments andEmerged Issues
The primary purpose of LBCDP was to promote economic
development of the Keihanshin region by transforming
Lake Biwa to a type of artiﬁcially regulated reservoir capable of providing additional 40 m3/s of water through the
Yodo River at times of extreme droughts, in order to ameliorate their adverse impacts (i.e., shoreline protection from
erosion, reconstruction of the water intake facilities,
renewal of ports and harbors, etc.) and those caused byﬂooding (levy construction around the lake, feeder river
ﬂood mitigation facilities, reconstruction of the Seta River
Weir, etc.). The design maximum drawdown at times ofextreme droughts is 1.5 m below B.S.L., and the design
maximum is 2.5 m above B.S.L. The newly created water
resources would be able to generate socioeconomic beneﬁts for the downstream Osaka and Kobe regions in the formof urban and industrial development. Shiga Prefecturalresidents, on the other hand, felt that they might be forced
to simply accede to downstream demands for additional
water without any direct beneﬁt from the transaction. They
were more likely to suﬀer from the additional discharge oflake water through the Seta River Weir, since it would
necessitate alteration of existing, or the construction ofnew, lakeshore facilities for coping with the lowered lakewater level. Thus, the contention of Shiga Prefecture wasthat the development of additional water resources should
not only beneﬁt only those living in the Keihanshin Region,
but also those living in the Shiga Prefecture. Thus, LBCDP
added the additional objective of contributing to thesocioeconomic status of Shiga Prefecture by providing forthe improvement of environmental and amenity enhancement infrastructure around the lake shore.

6.4.1 Legal Framework
With such considerations in mind, the “Special Measures
Act for Lake Biwa Comprehensive Development” wasenacted in June 1972. Article 3 of the Special Act stipulates
that LBCDP would be drafted by the Governor of Shiga
Prefecture and be approved by the Prime Minister, withthe project funds coming mostly from the national government and downstream local governments. A total of 22
project categories were identiﬁed and included in LBCDP.
Those component projects falling under “regional development” were carried out mainly by the National
Government, and relevant prefectural and municipal
Governments. The water resources development projects
and the Lake Biwa ﬂood control projects, on the other
hand, were implemented by the Water Resources
Development Public Corporation (>Fig. 17).
Thus, the conceptual basis of the comprehensive development plan was based on the following considerations:
1. Since those living around Lake Biwa have historically madetheir livelihoods from the lake, the lake should not be considered as a mere water impoundment or reservoir.
2. The lowering of the lake water level should be kept
within limits considered reasonable to those immediately aﬀected.
The balancing of the conﬂicting interests of Shiga
Prefecture upstream and the Keihanshin Region downstream required development of a conceptual framework
unique to the water resources management policy-making
institution in Japan.

6.4.2 Financial Framework
As a major national water resources development project,with ﬂood control and regional environmental and economic development for Lake Biwa and its watershed,
LBCDP needed a special scheme for ﬁnancing the component projects. The Special Measures Act for Lake Biwa
Comprehensive Development was speciﬁcally developed
for the purpose. The structure of the ﬁnancial scheme isillustrated in >Fig. 18. Brieﬂy, it includes the following
special measures:
1. Preferentially elevated subsidy rates: For some categories of component projects included in LBCDP, theEvolving History of Lake Biwa and Yodo River Basin Management

Lake Biwa
Development Projects

Regional
Development Projects

Roads (including roads
for management)

Sandbank

RiversMountain management

Dredging of the South Lake

Water supply

Forestation and forestry paths

Dredging of the Seta River(the only outlet river from
Lake Biwa)

Industrial water supply

Improvement of the Seta River

Fisheries

Management facilities

Harbors

Lake levees
Internal drainage facilities

Dam

Sewerage
Treatment of human waste

Land improvement for
agriculture

Acquisition of nature
conservation areas by publicbodiesTreatment of livestock effluent

Fishery harbors

Treatment of waste water fromagricultural communities

City parks

Refusal disposal

Natural park facilities

Waste quality inspection
facilities

500
450
400
350
300
250
200
150
100
50
0

Project Period⊡ Fig. 18
LBCDP budget structure.

Fishery

Original Plan
Fishing Harbour

Ag. Land Imp.

Wat. Supply

Reforestation

Mount. improv.

Ind. Wat. Supp.

Component Project

Sabo

1992 Revised
Dam const.

SewerageNightsoil
Dairy Was.
Rural Sew.
Solid Was.
WQ Monit.
Channelization

Billion Yen⊡ Fig. 17
Sub-projects in the Lake Biwa Comprehensive Development Project.

6

397

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6

Evolving History of Lake Biwa and Yodo River Basin Management

national government provided for “preferentially elevated subsidy rates;”
2. Financial compensation by the downstream local governments: The downstream prefectural and municipal
governments beneﬁtting from LBCDP agreed to makecertain compensatory payments to Shiga Prefecture
for the construction of needed facilities and their operations and maintenance. The cost sharing would bebased on the extent of water rights allocated out of the
newly generated 40 m3/s resulting from LBCDP. The
total compensation from the downstream governments amounted to be 60.2 billion yen. In addition,
Osaka and Hyogo Prefectures were required to pay an
additional 5 billion yen as a loan to Shiga Prefecture.
3. Lake Biwa management fund: At the completion of
LBCDP in 1996, Shiga Prefecture was permitted to establish what is called the “Lake Biwa management
fund,” totaling 10 billion yen, that will be used to undertake projects for maintaining the Lake Biwa water
environments and also to maintain and managementof the constructed facilities.

6.4.3 Extension of the Act and Inclusion of
Water Quality Improvement Projects
This Act was valid only for a 10-year period, to be terminated in March 1982. However, the social and economic
conditions of the nation, as well as the surrounding situation of the lake and LBCDP, have changed drastically during the period, with the surfacing of many new issues notadequately taken into account at the time of enactment. In
particular, because of the slowdown of the Japanese economy since the ﬁrst oil crisis in 1973, the national government spending on public works was severely curtailed,and LBCDP was able to achieve only 40% of the goals
stated in the Project plan by the end of March 1982. In
addition, the forecasted water demands by the downstream
Osaka region actually began to decrease soon after the oilcrisis in 1973, casting serious doubt about the validity ofthe very basis of LBCDP.
Furthermore, Lake Biwa water quality began to deteriorate much faster than anticipated, necessitating revision of
the original component projects. Thus, the Shiga Prefectural
Government consulted with concerned downstream governments and the national government in order to:
1. Extend the validity period of the Act for an additional
10 years to allow for the completion of the initiallyplanned projects
2. Revise the list of component projects by adding projects
dedicated speciﬁcally to water quality management

3. Maintain the current special ﬁnancing measures for
project implementation
The “Partially Revised Special Measures Act for Lake
Biwa Comprehensive Development” was enacted, promulgated, and put into force in March 1982. Four new
categories of projects added to the original list of 18 project categories include such items as agricultural dairy
waste management facilities, rural community wastewater treatment systems, solid waste management systems,
and water quality surveillance and monitoring systems.
The total expenditure increased signiﬁcantly from theoriginal 427 billion yen to 1.525 trillion yen. Together
with the originally planned expenditure of 351 billion yen
on water resources development and ﬂood control facility
development, the total expenditure eventually reached
1.9 trillion yen. >Fig. 19 provides details of the costs ofcomponent projects.
The upstream and downstream local governments
also reached a consensus in May 1982 that stipulates: (a)the need to establish a forum of joint study by the concerned local governments on the management of thewater quality of Biwa-Yodo Basin; (b) the joint ﬁnancial
obligation of the downstream governments to be ¥ 36.0
billion; (c) the extension of the pay-back period for the ¥5.0 billion left over from the previous years for an additional 10 years; and (d) the actual release of 40 m3/s tocommence only after the compensatory works have been
completed.

6.4.4 LBCDP Accomplishments and Legacies
Flood Control
Lowered Peak Water Levels by Dredging the Seta RiverAs shown in >Fig. 20, the increased discharge capacity of
the Seta River resulting from the regular dredging practiced since late nineteenth century has lowered the annual
peak lake water levels. Notable also was the risk reduction
in ﬂooding achieved for the lowlying areas along thelakeshore.
Lowered Flood Peak Water Levels by Prelowering

The lowering of the lake water level before the annual
ﬂood season, would lead to the peak lake water level being
held down. For example, there was an average rainfall of
257 mm over the period of 9 days in July 2006 over theLake Biwa catchment area. Because the lake water level
was initially at −0.2 m below B.S.L., the peak level was
being held to below the peak level experienced in July

6

Evolving History of Lake Biwa and Yodo River Basin Management

National Government (Ministry of construction) 3/4
Flood control

LBCD Projects

Flood control andWater Resource
Development(20.1%)

Down stream Government 1/4
Water Supply

Water Resource\ 35.13 billion(75.42%)
Nat,Gov (Ministry of Public Health) 1/3(79.9%)

Water User Organization

2/3

Industrial
Water Supply
Nat,Gov (Ministry of International(24.58%)Trade and Industry) *23.9%
Water User Organization

Regional Development*76.1%

National Government /Shiga Prefecture
Special Provisions for higher subsidy rates\ 155.42 billion

Downstream Financial Obligation

Loan \ 5 billion

LBCDP Fund Management Foundation

Osaka Prefecture 3.939 billion\ 5 billion

Hyogo Prefecture 1.061 billion⊡ Fig. 19
LBCDP expenditure.

B.S.L (m)(m3/s)
Annual peak water level caused by floods
Seta River Weir discharge capacity

3
2

800

+3.76m (1896)

the first Seta River Weirinstallation (1905)
New Weir installation(1961)

1
0

700
600

Seta River Weir
operating regulations(1992)

annual peak water level
has lowered

500
400
300
200

-1
S
Seta
River discharge capacity has
increased by dredging-2
1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
⊡ Fig. 20
Dredging the Seta River has brought down the annual peak water level in Lake Biwa.

100
0

Seta River Weir discharge capacity

Annual peak water level in Lake Biwa

4

399

6

Evolving History of Lake Biwa and Yodo River Basin Management

0

120
100
Lake Biwa Water Level (cm)400

5Peak in 1972 : +92cm

80
60

10
Normal water level
B.S.L +30cm

2 the peak water level reduced

as effect of the pre-Lowering

1540

Peak in 2006 : +51cm

20

20

Average rainfall in catchment area
in July 2006 flood
Lake Biwa water level in July 1972 flood25

Lake Biwa water level in July 2006 flood

300

1 Pre-Lowering by 50cm

before the flood season in
anticipation of heavy rain

-20
-40

35
Limited water level in flooding season : B.S.L -

Time

40

⊡ Fig. 21
Reduction of peak water level as a result of pre-lowering.

1972, when there was an average rainfall of 320 mm overthe period of 5 days (>Fig. 21).

when the maximum decline in water level was only −0.54 m(>Fig. 23).

Reduced Area and Days of Inundation near the Lake Biwa
shoreline

Expanded Wastewater Treatment Systems

Measures against the inundation caused by the trapping offeeder-river ﬂood water behind the embankments aroundthe lake could be reduced by pumping the inundationwater out into the lake, and also by increasing the lakewater discharge capacity through the Seta River Weir to
the Seta River. For example, although the peak water levelof the lake in July 1995, and that in 1972, were both at+0.93 m, the extent of ﬂooding in the former was muchless than in the latter in terms of the number of days ofinundation (>Fig. 22).

Water Resources Development
As an example of LBCDP achievement in water resource
development, the record drought of summer 1994 did notpose any severe threat in terms of water shortages, despite
the fact the lake water level declined down to the historical
record of −1.23 m. The number of days of water use curtailments during the 1994 drought was 44 days, or lessthan 50% of that experienced during the 1973 drought

Among the allocation of public funds invested for LBCDP
components, sewerage was highest, followed by land
improvement and road construction. Thus, they also areimportant in regard to impacts on the lake environment.
Sewerage

Sewerage construction was pursued primarily because of
its capacity to contribute signiﬁcantly to the improvementof Lake Biwa water quality, apart from its role in improving the living environment of the people. As a result, theproportion of service coverage in Shiga Prefecture, which
had been far below the national average, surpassed thenational average by the time LBCDP was completed. Manyof the municipal governments within the prefecture, however, face a serious ﬁnancial burden in having to repay theloan portion of the construction cost, in addition to theheavy costs of operation and maintenance, despite the fact
the subsidies by the national and prefectural governments
in connection with LBCDP was signiﬁcantly higher thansimilar undertakings nationally.

Evolving History of Lake Biwa and Yodo River Basin Management⊡ Fig. 22
Reduction in Area andDays of Inundation near
the Lake Biwa shoreline.

⊡ Fig. 23
Reduction in days of water use curtailment after LBCDP completion.

6

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6

Evolving History of Lake Biwa and Yodo River Basin Management⊡ Fig. 24
Fish ladder and draining-ditch aquatic habitat restoration work (Photos: By courtesy of Shiga Prefecture).

Rural Community Sewerage Project

The facility construction for LBCDP related Rural
Community Sewerage Project, under the jurisdictional
prerogative of the Ministry of Agriculture, started in 1982.
A total of 415 units for some 162,000 people have been
completed to date, of which 220 units for some 85,000
were ﬁnanced via LBCDP. The prerequisites to qualify forthis project included: (a) the number of beneﬁciallyhouseholds is more than 20; (b) the number of people to
be included in a single project site should be less than
1,000; (c) the area to be served by the system is not within
the planned service coverage area of the public seweragesystem administered under the jurisdiction of the Ministryof Land, Infrastructure, and Transportation; and (d) the
subject household area belongs to the priority area for
agricultural infrastructure development. The eﬄuentquality from these treatment plants are generally of highquality, far exceeding the eﬄuent standard. The individual
rural homes not served by the Project are provided withonsite treatment units, for which the Ministry of Healthand Welfare provide some subsidy.
The treatment facilities within this project scheme are
not equipped to treat industrial eﬄuents, unlike the casewith the municipal wastewater systems. One of the features of this sewerage system is that the communities
themselves take direct responsibility for its operation andmaintenance, and also bear their costs as the responsible
bodies in the management of these facilities.
Rural Nature Conservation Plan

Emphasis is also given to the restoration as well as enhancement of the Lake Biwa rural environment, particularly withrespect to ameliorating the aﬀected ecological habitats.
Speciﬁcally, a project dubbed as “the water beetle project”

has been promoted since 2006. The project aims at improvement of stream water quality, landscape preservation, andconservation of agricultural resource values. The project isﬁnancially supported by the prefectural government, and is
carried out by the rural communities, with the advice givenby the panel of experts. Some 28 projects, such as one
shown in >Fig. 24 of construction of ﬁsh ladder and instream water puriﬁcation, have already been completed.

Regional Economic Development
Land Improvement

Deployment of the land improvement project, including
farm land consolidation, is high for Shiga Prefecture,among the prefectures in the Kinki Basic Planning Region.
The irrigation system in the Lake Biwa watershed has
evolved over the past several decades with a number ofland improvement projects. Today, the paddy water may be
managed individually, thanks to the separation of irrigation and drainage, conversion of land to allow for irrigateddry-land paddy agriculture, and paddy land consolidation.
They have also helped the farmers to self-support farmmanagement. In spite of such improvements, however, thenumber of farmers in the watershed has declined, and mostof the remaining farmers have transformed themselves topart-time farmers. These new systems and practices also
have turned out to have damaged the natural ecosystemand biodiversity, which are subjects of major concern today
for those involved in paddy agriculture to pursue.
Roads

For Lake Biwa to meet both its ﬂood control and water supply needs through LBCDP, the lake water level has to beEvolving History of Lake Biwa and Yodo River Basin Management

accurately regulated on the basis of a set procedure, meaning
the lake had to be levied in response to ﬂow control at the
Seta River Weir. The constructed levies had a ﬂatted top toaccommodate passage of vehicles for levy maintenance.
The Shiga residents quickly saw the potential of this levy
road to be transformed into a major transportation routearound the lake, with link roads connecting to major coastal
communities and to the existing transportation networks.
The implications of this levy-cum-ring road are many.
For example, it has had signiﬁcant beneﬁts to the local andregional economy. It is used both as a local commuter roadand as a means of transporting local commercial goods. It
also had a signiﬁcant impact on the association of the population with the lake. The lake shore, which was hardly accessible before its construction, became quite accessible, notonly physically but also psychologically. The scenic view ofthe lake has changed. Those who previously only felt remotelyconnected to the lake began to feel much closer to it because
the lake is visible from the ring-road. Before its construction,
the lake water was hardly accessible from the shore for thecasual lakeshore visitors because the passage toward lake
was being prevented by the wetland paddy ﬁelds, as well as
the thick and tall aquatic vegetation, mainly of reeds. It
turned out to no longer be the case because much of the land
between the levy and the lakeshore has been converted torecreational parks. People now have a close-range view ofthe lake, in addition to a distant view. On the other hand, theenvironmental and ecological integrity of the shoreline also
has been drastically deteriorated by the construction of thelevy-cum-road structure, as well as by the drastic increase in
the extent of shoreline activities, making the subject one of
the most serious concerns emerging from LBCDP.

Coastal Zone Management
For centuries, growing rice in the complex network ofcreeks connecting numerous paddy ﬁelds was a major
form of agriculture along the shore of Lake Biwa. The farmland consolidation policy in the postwar agriculturalreform, however, gradually transformed the wetland paddy
agriculture to more dependable dry-land paddy agriculture. Though the paddy production became more eﬃcienton dry lands, the farmers’ mobility continued to be conﬁned to the lakeshore land due to lack of accessibility. The
construction of the levees as part of LBCDP, however, hada dramatic impact on both their life-style and their professional scope. The levees now prevent them from using thelakeshore as temporary agricultural land during the dry
season, a customary agricultural practice for centuries
prior to the construction of the levees. Further, with the6levees serving as an important transportation means along
the lake, the farmers no longer need to be conﬁned to thelakeshore land. They can choose professions other thanfarming. Also, the extent of the shoreline farm lands was
reduced through the newly introduced LBCDP policy forthe government to purchase the farmland for public use.
Finally, the relative importance of this previously primaryindustry was also decreasing, leading to migration of the
population out of the shoreline communities.
Prior to LBCDP, the main stakeholders using the coastal
environment were those living in proximity to the coasts,
including wetland paddy farmers, ﬁshermen, reed harvesters, tour boat operators, and others aﬃliated with related
professions, whose livelihoods depended on the resource
values provided by the lake. Thus, the management objectives and the means for achieving them were rather straightforward. Today, 40 years after inauguration of LBCDP, thestakeholders have grown in number and in kind, and theirvested interests have also greatly diversiﬁed, making theirmodes of engagement much more ﬂexible.

Changed Economic Profile
of Downstream Region
Industrial Maturation and Change of Policy Concerns

After exceeding the national average in 1981 and reachingamong the tops in ranking in the 1990s, the per capita
income of Shiga Prefecture has continued to increase,
today being in the top third or fourth place among the 47
local governments. Although the proportion occupied by
the tertiary industry is higher than that occupied by theother industrial categories in other prefectures, in terms ofthe gross prefectural product, the proportion of the secondary industry is higher than that of the tertiary industry
in the case of the Shiga Prefecture. As previously discussed,
the relocated industries from the downstream region to
Shiga Prefecture in the 1970s and 1980s have contributed
to this trend.
Japan’s industrial proﬁle has changed signiﬁcantly overthe past decades because of several major factors. First, hereconomy transformed from a developing one with a highgrowth rate in the 1960s and 1970s, to a mature one with alow growth rate in the 1980s. Trade globalization since thesecond half of the 1980s has also had a major impact on its
industrial proﬁle, particularly since many of the manufacturing industries began to relocate their facilities overseas,
while decreasing the number of newly established industries
within Japan. This brought about what is called the deindustrialization problem, that is, ﬁrms began to reorganize
the production networks, consolidating and reorganizing

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Evolving History of Lake Biwa and Yodo River Basin Management

their production facilities and related operations to fewer
and fewer numbers. Shiga Prefecture was among those thatbegan to experience this dilemma. When an industrial
facility is closed, it can be readily noticeable, but if the functions of an establishment change, this change would not be
so readily apparent. For example, an industrial establishment dedicated to manufacturing may transform itself to
one dedicated to a research-and-development function.
Although such a change would not be easily observable, theimpact of this transformation could be profound, in that theoverall industrial capacity may be signiﬁcantly changed.
Further, such a change would impact the employment
situation. In the 1960s and 1970s, the surplus labor in theentire region of Keihanshin was absorbed by the accumulation of industries within itself, contributing to its stable
employment proﬁle. However, this situation no longer
holds today. This is typical of an economy in maturity, witha likely tendency toward a new unemployment problem.
The industrial policy, therefore, has to facilitate the conversion of the existing labor force in a way that allows it to
be able to cope with the emerging needs, or to stimulate
the new business responsive to the emerging market needs
under economy in maturity.

from the scientists and the mass media, but also strong
opposition from various environmentalist groups. Amongthem was a citizen group formed of concerned scientists
and citizens who ﬁled a lawsuit against the central andlocal governments, particularly with respect to the damage caused to the lakeshore environments by the construction activities across the entire shoreline (levyconstruction), by the construction of a man-made island(on which an oversized wastewater treatment plant was
to be constructed), and by dredging carried out in theSouth Lake and along the river mouth of the Seta River.
The trial started in 1976 and was concluded in 1989, withthe court decision refuting most of the plaintiﬀs’ claims.
Although this trial had only limited impact in the implementation of LBCDP, it did contribute greatly to the
movement toward ecosystem restoration, which ironically subsequently became the main theme of the postLBCDP policy.

6.5 Post-LBCDP Developments
6.5.1 Changes in Downstream Water
Demands

Expansion of Metropolitan Area

The economic geography of the Lake Biwa region is highly
sensitive to the regional mobilization of goods and services that, in turn, depends on the availability of regionaltransportation networks. In the early 1960s, the transportation networks began to be expanded toward the easternpart of Lake Biwa, enabling the network to be connectedto that of Keihanshin through the already-existing network in the southern part. The networks have grown toreach the Kosei (the western part of Lake Biwa) with thecompletion of Japan Railway (JR) Kosei Line in 1974, andKohoku (the northern part of Lake Biwa) by the completion of the Hokuriku National Motor Expressway in 1980.
Additionally, they were linked through the nodal points
within the Lake Biwa region (such as Maibara in thenorth), with Japan’s major transportation arteries developed in 1960s, connecting the Keihanshin region withsuch megalopolises in the east as Nagoya and Tokyo.

6.4.5 Environmental Conservation
Problem and Lake Biwa Lawsuit
Being a massive infrastructure development project, it
was feared from its onset that implementation of LBCDP
would have serious implications for the lake’s ecosystem
integrity, inviting not only heated debates on its merits

As previously discussed in Section 6.3, the management of
the Lake Biwa-Yodo River water has been greatly aﬀectedby the water demand proﬁle in the downstream Osaka Bay
region, particularly in relation to its industrial activities.

Implications of Changes in Industrial
Profile Along Osaka Bay Region
Over the course of decades spanning two World Wars,
many nuclei of small industries scattered throughout
Osaka, Kobe, and their surrounding suburbs were consolidated to form a major industrial zone called theHansin Industrial Belt stretching around the Osaka Bay
area. By approximately the 1950s, this industrial zone
gradually expanded in two major directions, that is,
toward Himeji, the western part of Hyogo Prefecture(called the Higahi-Harima region), toward Sakai and thesurrounding municipalities and northern Wakayama
Prefecture (called the Senshu region), and also alongside
the Yamato River toward Nara in the east and alongside
the Yodo River toward Shiga Prefecture in the north(Lake Biwa region). The Bay region industrial complex,
in particular, evolved to specialize in water-intensive,
basic material type industries, while the inland region
evolved to specialize in processing and assembly type

Evolving History of Lake Biwa and Yodo River Basin Management

industries that were less water-intensive. The former
industrial complexes began to face serious problems by
the early 1970s. The ﬁrst problem was industrial pollution created by the complexes. There were many cases ofenvironmental pollution incidents, compounded by serious human health issues. The second problem was theland subsidence along the Osaka Bay coastline due to theover-extraction of groundwater during the postwar
industrialization. The typhoon-induced high tides in1961 inﬂicted serious damages to the coastal region, duein large part to land subsidence, accompanied with a lossof several hundred human lives. Further, there was awater shortage problem. The increasing demand forindustrial water, accompanied by the need to curtail overextraction of groundwater, motivated the politicians andgovernments in the region to seek a greater water releasefrom Lake Biwa to the Yodo River. This eventually led tothe inauguration of LBCDP.

6

relocating industries and workers were supposed to besettled in industrial parks located in the urban improvement zones to be established in areas approximately morethan 50 km outside of the existing metropolitan regions(the eastern Lake Biwa zone, the central Tamba zone in
Kyoto Prefecture, the Harima zone, the Wakayama zone).
Although the aim of this new policy measure was the diffusion of industries out of the metropolitan centers, it was
not necessarily uniformly accomplished. Since housing
and industrial developments tended to seek the available
land along the major transportation routes, such as JR
Tokaido and other private railroad lines, as well as the
Meishin National Expressway, the eastern Lake Biwa zone
was a popular destination for relocation, in contrast to
the other zones, resulting in an imbalance in industrial
activities and population distribution among the urban
improvement zones.

Changing Water Demands
Regional Development Policy andRedistribution of Industries
Japan’s evolving regional development policy also had asigniﬁcant impact on the management of the Biwa-Yodo
Basin. The major emphasis in Japan’s post–Second World
War regional development policy was to reduce the excessive pressures put on major metropolitan areas. In the
Kinki Basic Planning Region (encompassing Fukui, Mie,
Shiga, Kyoto, Osaka, Hyogo, Nara, and Wakayama
Prefectures) within the Osaka Prefecture, the number offactories in Osaka City was about 60% of the total numberin the Planning Region in 1965, when the population of
Osaka City surpassed 3 million at its peak. Osaka City also
had 52% of the number of workers in the Planning Region,and 53% of the industrial shipments. It was much the samewith regard to Kyoto, in relation to the Kyoto Prefecture.
The law introduced in 1964, restricting the siting of largescale factories, was aimed at restricting large-scale factories in parts of the Municipal boundaries of Osaka, Kyoto,
and Kobe, as well as in the connecting Hanshin Belt Zone.
However, it turned out that the only designated area available to accept those relocated factories was the Harima
Industrial Park in the Himeji Prefecture, west of the Hyogo
Prefecture.
The need for a legal basis for industrial relocation wasaddressed with the provision for development of the Kinki
Basic Planning Region Improvement Plan, as stipulated in
the Kinki Basic Planning Region Improvement Act of
1963, in which the Region was divided into the existing
metropolitan zones, suburban improvement zones, urban
improvement regions, and conservation zones. The

Over the past decades since the inauguration of LBCDP
in 1972, the water demand structure in the Biwa-Yodo
Basin has undergone signiﬁcant transformation as aresult of changes in the industrial economy. First, overthe period between the mid-1970s through mid-1980s,
the declining economic growth brought about a change
in the mode of industrial production. Speciﬁcally, theindustries had to overcome the energy price hike triggered by the successive oil crises in 1973 and 1979. They
had to adjust their processes to achieve higher production eﬃciency by curtailing energy and water uses.
Further, the industrial structure has changed from one
primarily focused on manufacturing basic industrial
goods, to one more focused on the assembly of manufactured goods. This change has also led to lower water consumption per unit of production output. In addition, overthe period between the mid-1980s through today, a large
number of industries shifted their production base tooverseas, to take advantage of lower labor and facility
development costs. The strong value of the Yen after the
Plaza Accord in 1985 also helped this trend, also contributing to a direct decline in industrial water demands inthe region.
There are emerging eﬀorts being made for structuraltransformation and revitalization of the Osaka Bay
region economy today through large scale projects in
information technology and service economy in responseto economic globalization. However, these newly formed
large-scale projects, or even the relocation of large-scaledomestic production facilities, do not seem to be increasing the water demands.

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Evolving History of Lake Biwa and Yodo River Basin Management

6.5.2 Restoration of Ecosystem Integrity
and Water Quality
Differences in Upstream and Downstream
Perceptions of Water Quality
The upstream and downstream jurisdictional entities in
the Biwa-Yodo Basin have experienced long-term conﬂicts
arising from the management of water quantity. The conﬂicts have been somewhat mediated through the compensatory transactions from the downstream and central
governments to the upstream Shiga Prefecture, through
LBCDP. The conﬂicts have not existed for water quality inthe sense that everyone wants improved lake water quality,
although it is not clear how much improvement is needed,or who will bear the costs of the improvement. Parts of theexpenditures on water quality improvement are defrayedthrough the natural and environmental conservation
component of LBCDP. Although the original expectation
was that the amount of investment under this category
would be suﬃcient to realize signiﬁcant improvement inlake water quality, the improvement was only marginal at
the time LBCDP was completed in 1997. The Shiga
Prefecture wanted the downstream governments to continue to contribute ﬁnancial resources, even after LBCDP,
for improving the lake water quality.
If the scope of water quality improvement is conﬁned
to water supply, asking the downstream water users formore funds would not be easily justiﬁed. The quality of thedrinking water was already more than satisfactory, thanks
to investments made in the 1990s for advanced treatment
technologies, the cost for which were also borne by themselves. They were not experiencing any taste and odor
problem, even during algae blooms. Thus, they would see
no point in utilizing more funds to improve the overall
quality of Lake Biwa water.
The issues pertaining to ambient lake water quality are
diﬀerent from those pertaining to drinking water quality.
First, the ambient water quality target levels for lakes inJapan are expressed in terms of such quality parameters as
Chemical Oxygen Demand (COD), Total Nitrogen (TN),and Total Phosphorus (TP), these parameters being usedmainly to assess the state of eutrophication. This is in addition to their suitability as drinking water sources forhuman consumption. The Shiga Prefecture and its residents want to reduce, if not eliminate, the incidence ofalgal blooms associated with eutrophication, maintain theecosystem health for aquatic fauna and ﬂora, eliminate
invasive species, and improve sediment quality. The concern of the Lake Biwa residents encompasses a broad
spectrum of intangible beneﬁts to be shared and enjoyedby people over many generations to come. How convincing
such an argument would be depends not only on the willingness of the population to pay for such long-term objectives, with full understanding of the value of protecting
the lake and its basin, but also on its capability to pay. The
implication is that the emerging structure of the basinwide water resource management would be dictated by
the capability of the people and governments to adjust
to emerging water quantity and quality factors, many ofwhich were unknown at the time of inception of LBCDP.

Lake Biwa Comprehensive
Conservation Plan (LBCCP)
Though it took much longer than originally projected(25 years, rather than 10 years), basically all the approved
LBCDP component projects were properly completed by
1997, under each of the three major project categories, thatis: (a) water resources development for Shiga and downstream water users; (b) ﬂood control around Lake Biwa
and along the Yodo River, and (c) environmental infrastructure development along the Lake Biwa shoreline andaround the watershed. While the downstream governments acknowledged LBCDP accomplishments, theirgained beneﬁts were more of an expectancy nature, that is,more water during times of severe droughts (which may
happen once in 10 years), and reduced loss of property
and human lives from major ﬂood incidents that may happen once in a few hundred years.
On the other hand, the beneﬁts gained from LBCDP
for the Shiga government and its residents were more
direct and explicit. They saw ports and harbors renovated,levies and embankments constructed around the lake that
also now serve as a major artery road around the lake,
paddy lands extensively improved with large-scale pumping facilities for irrigation with lake water, and even basic
urban infrastructure provided for industrial developments. The Shiga population has increased by nearly threequarters of a million over the period of LBCDP implementation, and its per capita income, which was previously ranked as one of the lowest among the 47 prefectures,increased to be among the top incomes, thanks largely tothe transformation of the Shiga economy from being primarily agricultural in nature to being primarily industrial,
due in part to migration of population and industries
from the downstream Osaka region to the Lake Biwa
watershed.
This dramatic change in the proﬁle of Lake Biwa
watershed, now very urbanized and industrialized, alsomeant the paddy-wetlands along the lakeshore, which

Evolving History of Lake Biwa and Yodo River Basin Management

used to provide proliﬁc ﬁsh habitats, have been lost. During
the same period, quite extensive land conversions also
have taken place, for example, from paddy land to housing
and industrial estates, forest land to industrial estates, etc.
Thus, despite the introduction of signiﬁcant structural andnonstructural environmental control measures, the water
quality and ecosystem integrity of the lake and its watershed began to deteriorate. While the point source pollution load has been signiﬁcantly reduced as a result of thesewerage coverage implemented during this period, therestoration of the natural self-puriﬁcation capacity lost
through transformed land uses, remained as a major challenge at the time of LBCDP completion.
Consequently, toward the terminal years of LBCDP, theShiga government decided to pursue a new post-LBCDP
project focusing on ecosystem restoration. In March 1997,
Shiga Prefecture compiled the results of the deliberations ofa national council established for this purpose, and prepareda plan called the Lake Biwa Comprehensive Conservation
Plan (LBCCP), dubbed “Mother Lake 21 (ML21).” The planemphasizes that the ultimate solution to the problems facing
Lake Biwa lies in restoration of the natural and ecosystem
capacities of the coastal zone and watershed, while also pursuing the revival of an environmental culture to allow such
retransformation to occur. While Shiga Prefecture wanted
the national and downstream governments to be sympathetic to enactment of a special legislation for ﬁnancial
arrangements to help it achieve its long-term ecosystemconservation objective for Lake Biwa, the response from thenational and downstream governments was not so accommodating. They courteously declined to facilitate ﬁnancial
arrangements to the Shiga Prefecture.
What then is the ML21 Plan? In fact, it is more a vision
than an infrastructure development plan, as in the case of
LBCDP. It is not accompanied by any legislated special
ﬁnancial provisions. Those projects that fall within theframework of this vision are ﬁnanced basically under sectoral budgets, with some preferential subsidy based on
their merit within already-existing sectoral plans and programs. Speciﬁc elements of the ML21 plan are as follows:(a) Targeted Geographic Coverage
The target area was set to include the jurisdictional
area of the Shiga Prefectural Government, although it
also takes cognizance of the implications to the downstream Yodo River region;(b) Planning Horizons
The speciﬁed period is 22 years, from April 1999 throughMarch 2020, in two phases; the ﬁrst is from 1999 to2010, and the second from 2010 to 2020. The provisional
long-term planning horizon has been set at 2050.

6(c) Measures of Achievement
Plan categorized the measures of achievement in termsof improvement: in overall quality of Lake Biwa water, inwater inﬁltration and retention capacities of watershedsoils, and in natural environment and landscape ecology. It also stipulated the need for promotion of citizen
engagement and networking at sub-basin levels acrossthe watershed. Information dissemination and researchpromotion were also an important component.
(d) Compatibility with Other Plans
The comprehensive conservation plan is meant tobe consistent with plans formulated by the central
government, including the Comprehensive National
Development Plan, the National Land Use Plan, andthe Basic Facilities Plan for the Kinki Region, as well asplans formulated by the prefecture, including its longterm vision called New Lake Country Story 2010, andits Environmental Master Plan.

Appraisal of First 10 Years of LBCCP(1998–2010)
In March 2010, with the ﬁrst phase of LBCCP having
reached its terminal year, and the second phase about to belaunched, the LBCCP scientiﬁc advisory committee issued
a review report of the ﬁrst phase, with recommendations
for the second phase. The report’s appraisal is that the Plan
has generally played a signiﬁcant role as a long-term vision
for Lake Biwa, with the ﬁrst phase attaining some signiﬁcant achievements.
Speciﬁcally, in regard to improved quality of Lake Biwa
water, the achievement during the ﬁrst phase has been signiﬁcant, particularly in regard to water transparency andthe concentration of TP. In contrast, the rate of reductionin the TN concentration was not as impressive as that for
TP. In fact, the altered balance between the phosphorus
and nitrogen concentrations has led to a change in types
and numbers of phytoplankton species, that is, a decreased
variety of species but an increased number of smaller, andmore nuisance, species thriving in lake water. Further, thedissolved oxygen concentration in deeper parts of theNorth Basin has been exhibiting a decreasing trend. The
COD has actually gradually increased during the period, apuzzling phenomenon whose implications are not yet
clearly understood scientiﬁcally. In terms of the inﬂowing
pollution load, the point-source contribution has been signiﬁcantly reduced, although the nonpoint contribution
remained much the same as 10 years before.
In regard to improved water inﬁltration and retention
capacities of the watershed soils, the results are not so

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Evolving History of Lake Biwa and Yodo River Basin Management

signiﬁcant. Between the ﬁscal years 1997 and 2006, theareas for agricultural and forest lands, respectively,
decreased by 0.5% and 5.5%, while the areas for housing
land and for road, respectively, increased by 7% and 8%,
the rates being comparable to, or exceeding, the nationwide averages. Such simple measures indicate the preservation of forest and farmland for rainwater inﬁltration has
not been progressing in the desired direction. The appraisal
document states that there must be serious consideration
given to halting the ever-increasing trend of land conversion from ones exhibiting natural water inﬁltration andretention capacities to ones that do not. It is also pointed
out that, for forest land to improve water inﬁltration andretention capacities, the forests themselves have to be wellmaintained through thinning and clearing of nuisancevegetations. However, of the artiﬁcially forested land
requiring such maintenance, only 65% of the land wasmaintained as of ﬁscal year 2008. Thus, the appraisal report
proposes that the Plan needs a more strategic approach instrengthening the institutions for undertaking maintenance operations, even to the extent of exploring a policy
for developing “the green corridor” all the way from themountain ranges through ﬂat land toward the Lake Biwa
shorelines. Additionally, the appraisal report points out theneed for the existing water use practices to be further
reﬁned to minimize wasteful use of irrigation waters, bydevising appropriate instrumentation. It further points
out the need to assess the viability of existing irrigationwater recycling schemes, giving due considerations totheir cost eﬀectiveness for the purpose of the LBCCP. The
emerging issues included the deteriorating forest lands
due to spreading tree damages from insect pests and nuisance animals. The report points out, more profoundly, theneed for the Japanese forest industry to gain competitive
strength over inexpensive imported forest products so thatan institutionalized system of forest maintenance would
be established both for providing for economic viability
and for healthy forest land.
The report also points out that the ﬁrst period target
was not very clear for the on-the-ground implementationof plans and programs, particularly with regard to “landacquisition for ecosystem restoration.” Further, the activities stipulated under this category were limited in number and extent of spatial coverage, indicating theinadequacy of the pursuits under this category of activities, with most of the issues identiﬁed before the LBCCP
still remaining problematic. Further, there are issues andproblems that did not exist before the LBCCP that areposing major threats to the natural environment andlandscape ecology of Lake Biwa, including such problems
as the loss of habitat for indigenous species of ﬁsh, andthe proliﬁc growth of macrophytes in the South Basin of

Lake Biwa, particularly in relation to the changed operational procedure of Seta River Weir, all indicating that the
future of the LBCCP is directly linked to the Yodo River
System improvement policy.

Amendment to the Lake Water Quality Law
The Lake Water Quality Law (the Law concerning Special
Measures for Preservation of Lake Water Quality, 1984)
was amended in 2005, noting that the stagnant achievement level of water quality targets that is only a little over
50% as in 2004 (see Chap. 7 for details in the case of Lake
Biwa). The Amended Law provides for the establishmentof special area for nonpoint pollution control, that is,requiring pollutant load control measures from nonpoint
sources and formulates plans to implement measures
within the designated urban areas and farmlands. The newpolicy tools under this amendment include new regulatory standards, speciﬁcation of categories of aquatic plants
to be protected, and notiﬁcation of the permitted activities
in the lakeside environment protection areas. Althoughthese policy tools, such as development of an emergency
action plan water environment improvement, are expected
to serve well for the enhancement of ecosystem propertiesof Lake Biwa, many of the included measures, including
the establishment of protection and preservation areas(e.g., the reed bed protection areas) are already part of theLake Biwa ordinance.

6.5.3 The Changed Agenda
Amended River Law of 1997
The ﬁrst River Law in Japan was enacted in 1896 after theoccurrence of a series of large-scale ﬂoods in previous
years. The ﬁrst Law was subsequently revised in 1964 withthe aim of delineating the responsibility of the Central
Government and Local Governments in managing the different classes of rivers, and to set the basic design ﬁgures
for ﬂood control for each class. Over more than three
decades, the 1964 Law played an instrumental role forpost–Second World War Japan to meet various river management needs, including ﬂood control and water resources
development.
The 1964 River Law was amended in 1997, basicallyto cope with increasing public outcries against the lackof a consultative process involving potentially aﬀected
local stakeholders and environmental citizen groups
that strongly accused the river improvement works ofhaving caused serious ecological damages to the riverine

Evolving History of Lake Biwa and Yodo River Basin Management

environments. The Amended River Law now includes
some important provisions to address these points. For
example, Article 1 stipulates the purpose to be “to contribute to land conservation and the development of thecountry, and thereby maintain public security and promote public welfare, by administering rivers comprehensively to prevent occurrence of damage due to ﬂoods,
high tides, etc., utilize rivers properly, maintain the normal functions of the river water by maintaining andconserving the ﬂuvial environment” (Ministry of Land,
Infrastructure, Transport, and Tourism 1997). It also
stipulates the need for each river administrator to establish a plan to improve the river concerned, that is, the“River Improvement Plan” (hereafter referred to as the
Improvement Plan) in accordance with the “Fundamental
River Management Policy,” (hereafter referred to as theFundamental Policy) speciﬁed for river.
To fulﬁll the stipulated purpose, the 1997 River Law
provides for three feature considerations that did not exist
in the Original 1964 Law:(a) The concept of “river environment” as being equallyimportant as ﬂood control and water withdrawals for
consumptive and nonconsumptive water uses(b) The need for broader participation of stakeholder
groups and sectors in the process of developing a river
improvement plan(c) The process of acceptance and approval of the river
improvement plan through a societal and politicalprocess of consensus building
In regard to the concept of river environment, the Law
aims to facilitate the necessary protection and maintenance works to protect animal and plant habitats, and also
to preserve the scenic and other intangible values associated with a river system. The Law also stipulates the needfor the river improvement plan to be consistent with theComprehensive National Development Plan and the Basic
Environment Plan of the regions.
To address the goal of broader stakeholder participation, the Law stipulates the responsibilities of river administrators to:•••Consider opinions from persons with relevant experience or an academic background when necessary
Take necessary measures, such as public hearing, etc.,
to reﬂect the opinions of the people concerned whenever necessary
Consider opinions from concerned prefectural governors and mayors in advance, as provided in Government
Ordinances

Regarding the process of consensus building, it is totake place in several steps over a period of a few to several

6

years, to ensure that the considerations identiﬁed in items(a) and (b) above would be properly integrated in the formalized process.

Development of Yodo River
Improvement Plan
The Amended Law stipulates the process of formulating
the Fundamental Policy and of developing the
Improvement Plan, to be administered by the river administration division of the Kinki Regional Bureau (hereafterreferred to as the Bureau) of MLIT in the case of the Yodo
River. The process takes the following process:(a) Fundamental Policy• A draft Policy to be prepared by MLIT
• The draft to be reviewed by the Infrastructure
Development Council established under MLIT
• The adoption and announcement of the Policy by
MLIT(b) Improvement Plan
• A draft to be prepared by the Bureau, appropriately
reﬂecting the broad public sentiments and vested
interests• The draft to be revised as appropriate, resorting to, as
needed, the expert opinions and the aﬀected parties• The draft to be provisionally ﬁnalized• The draft to be accepted by the prefectural governors within the Yodo River basin• Adoption and announcement of the ﬁnalized Plan
by MLITIn the case of the Yodo River system, the process included
preparation of a few more intermediate outputs by the River
Basin Committee, to be elaborated below. They area Proposed
Conceptual Framework (hereafter referred to as the
Framework), a Provisional Basic Plan, and the Basic Plan.
For the Yodo River system, the Fundamental Policy
was issued in August, 2007. The Improvement Plan was
declared as being completed, and was published in March,2009 by the Bureau. It was after almost several years ofintense and heated exchange between the Committee, theBureau, citizens, NGOs, and various local governments.
The following is a brief account of the long, complicated and controversial sequence of events that took place
between early 2001 to data.
Establishment of River Basin Committee

In February 2001, the Bureau took on the process of developing the Improvement Plan, and launched the process of
forming the Yodo River Basin Committee (hereafterreferred to as the Committee) as a body consisting of

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6

Evolving History of Lake Biwa and Yodo River Basin Management⊡ Fig. 25
Some Contentious Points argued by the Committee against the Need to Construct the Niu Dam (If, in early stages of
expected severe droughts, the Lake Biwa water level can be lowered, the maintenance flow of the Oh River can be reduced,
and also the water supply curtailment policy is instituted at the same time, then, there will be no need for the constructionof Niu Dam).

“persons with experience or an academic background.”The hope was that the Bureau would be able to beneﬁt
from close collaboration with the Committee in its pursuitof the development of what could be an extremely complicated and conﬂicted Improvement Plan needed to meetthe expectations of the basin population over next 30 years
or so. It would have to fulﬁll their overall needs, that is,
ﬂood control, water resources provision, and environmental and ecosystem services of the river system, for the subbasins represented by local governments, with diﬀerent
priorities and parochial vested interest fostered over centuries. Among many other issues to be elaborated in the
Improvement Plan was an issue of whether or not to proceed with the construction of four dams (Yono-River,
Daido-River, Niu, and Kawakami Dams) and the renovation of an existing dam (Amagase Dam) (see >Figs. 25 and26). Prior to the establishment of the Committee, thesedams were in some preparatory phases of construction.

Proposed Conceptual Framework

At the outset, the Bureau decided that the Committee
members to be selected totally independent of any involvement of the Bureau itself, so that the established Committee
would not be regarded as being biased for or against a particular set of sector or stakeholder interests. The Bureau
also agreed for the Committee to prepare a conceptual
framework for development of the Plan. By January 2003,
the Committee completed the Framework and submitted it
to the Bureau. Under the part pertaining to river improvement, it stressed the following four factors:••

The precautionary principle, based on a holistic framework of analysis
The need to enhance the cultural, traditional, historicalvalues and features, while ensuring the river improvement needs are met by the entire basin and the society
as a whole

Evolving History of Lake Biwa and Yodo River Basin Management

6⊡ Fig. 26
Some Contentious Points argued by the Committee against the Need to Construct the Kawakami Dam (For meeting thewater demand of the Iga District, the Osaka Prefecture may be willing to transfer its Shorenji Dam water right for use by the
Iga District, the Osaka Prefecture may be willing to transfer its Shorenji Dam water right for use by the Iga District, so that
there will be no need for the construction of the Kawakami Dam).

••

The mechanism wherein the basin citizen at large
would play an important role
The need to implement planning assessment and pursue adaptive management

Further, under the part pertaining to the fundamental
philosophy, the Framework recognizes the need to conserve and restore the river ecosystem, and states that “theultimate goal of this Amended River Law is the preservation and recovery of a river ecosystem.” It also states “theimplementation of the Improvement Plan should not
result in reduction of the existing species of ﬂora andfauna, nor should it result in further deterioration of theecological integrity that is so crucial for sustainable livingof the people.” Finally, it pledges that “it is the grave duty ofthe present generation to succeed the rich natural environment of the Yodo River system properly preserved andrestored for the future generations.”

Issues of Dam Construction

In regard to the construction of dams, including thosealready in the process of construction, the Framework
states that, “The dams should not, in principle, be constructed in view of their possible serious impacts to thenatural environment of the river basin system, and, if theconstruction of a dam is to be pursued, it should be only
after all alternative possibilities have been exhaustively
examined to prove that the attainment of the river management objective would be possible only with its
construction, and the society at large would support that
conclusion. As for the possibility of increasing precipitation due to climate change and the consequent societal
consent with the need for dam construction, the decision
will have to be made adaptively.” The Framework’s progressive assertion was regarded by the media as possibly
inﬂuencing the mindset of the general public that havelong wondered whether or not the use of their tax money

411

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6

Evolving History of Lake Biwa and Yodo River Basin Management

for large-scale public works such as dam construction
would continue to be justiﬁed.
In the meantime, the major downstream water users,
such as Osaka City, Osaka Prefecture, and Hanshin Water
Supply Corporation quietly took advantage of the ideas
imbedded in the Framework regarding the those dams
that they agreed to with MLIT and the Water Resources
Development Cooperation to share the construction
costs. They in eﬀect admitted that future demands forwater that they had projected decades ago have provenwrong, and the storage capacity of the dams allocated forsuch purposes would no longer be needed. The very presence of the Committee seemed to have made it easy forthem to make that move, about which they had long been
in a bind.
Yodo River Improvement Basic Plan

Taking full note of the Framework, the Bureau formulated
and made public the Basic Plan in June 2004. Developmentof the Basic Plan required an unprecedented collaboration
between the Bureau and the Committee, conducting a
total of hundreds of joint activities consisting of expert
group meetings, workshops, on-site observation tours, andconsultative meetings with local residents. The Basic Plan
made clear that the conventional approaches concerning
river improvement would have to be fundamentallyrevised, based on the recommendation stipulated in the
Framework. The ﬁve main points stipulated in the Basic
Plan were as follows:
1. Flood control, water resource development and management, and environment and ecosystem considerations would be placed within one uniﬁed framework.
Major emphasis previously had been placed only on
the ﬁrst two considerations, seriously neglecting environment and ecosystem considerations.
2. Utmost priority would be given to protecting human
lives, meaning that the conventional approach to ﬂood
control, that is, containing the projected ﬂoodwaters indams and their excess within the river embankments,
would have to be reconsidered. The Plan should now
include a range of structural and nonstructural approaches, including minimization of ﬂood damages
and saving of human lives by temporarily vacating
people in the potentially high-risk residential areas,
with a range of risk avoidance measures supported byproper forecasting and information sharing. The policy shift to be achieved in the Plan therefore is from“ﬂood control” to “ﬂood management.”
3. Construction of new water control facilities would be
minimized by directing the policy toward more rational use of the existing facilities, greater water demand

management, and more rigorous implementation of
nonstructural measures.
4. The perimeter land between the water channel andthe embankment, often used for gardening, sporting
grounds, golf courses, and other uses without permits,will have to be cleared to allow for greater leverages for
ﬂood control and restoration of ecosystem integrity.
Construction of dams should be avoided if at all possible, giving full consideration to their potentially adverse
eﬀects on river environment during their construction,and taking the severe hardships to people living in theareas designated to be submerged fully into account. Ifthey are to be constructed, a thorough and convincing
explanation should be given to, and be accepted by, thebasin community at large, regarding its necessity, urgency,
and environmental impacts.
Over the next four years, however, a number of complicated turn of events took place, involving various societal
sectors with conﬂicting views on this particular decisionby the Bureau. Those communities and residents who had
already been relocated from the proposed dam sites, forexample, felt they were betrayed by the Bureau, and vocally
expressed their anger against the Basic Plan. They hadbarely overcome the psychological hardship of submitting
their precious land for the beneﬁt of the public at large.
There also was the issue of compensatory payments alreadybeing made by the Bureau to those having to give up theirproperties and homeland job opportunities. If the dam
construction would not proceed, these compensatory considerations would also be subjected to criticism, leaving
them with a lost sense of identity. As another example, themunicipal governments that had been counting on thedam to cope with ﬂood and drought risks upon its completion would now have to seek alternative means of copingwith such risks. Further, those entities already having madeinstallment payments for expected beneﬁts of dam construction want to have the payments returned. The otherside of the coin, of course, was the issue of penalty payments to the Bureau from those expressing a desire to now
withdraw from the originally agreed plan of decades ago of
having the dams constructed with a cost sharing scheme.
Outline of the Yodo River Improvement Plan

The ﬁnalized Yodo River Improvement Plan consists of six
goals of river management and the measures to accomplish them. Six goals are as bellows;(a) Interaction between people and nature
The purpose is to establish relationships between people and river in such a way that people would be interested in, be willing to interact with, and be thinking

Evolving History of Lake Biwa and Yodo River Basin Management

together about the river. So that, people will be able totake adequate actions at a time of ﬂoods, and thedownstream riparian and the upstream riparian will
be able to increase the understandings each other.
(b) River environment
The purpose is, based on an idea that “the sustainableecosystem is essential for human life and activity,” topreserve and restore the habitats for various species,
including endangered species and other endemic species, with observing the eﬀects on river ecosystems.
(c) Flood management and disaster prevention
The purpose is to promote both structural and nonstructural measures to minimize the damages caused byany kind of ﬂood as much as possible. At that time, themeasures should be taken in cooperation with the riparian in the whole basin, based on the policy to improvesecurity from ﬂooding in the entire river system, rather
than sacriﬁcing one area of a region to protect another.
(d) Water resources
The purpose is to promote the eﬃcient water utilization, taking the recent population decline and harmonies with river environment into account, and to prepare
for the possible serious drought due to the global climate change.
(e) Utilization
The purpose is to ensure the integrated river management and improvement with community development,
because Yodo river ﬂows mainly through the urban
region(f) Maintenance
The purpose is, taking the aging facilities and the life
cycle cost into account, to execute the eﬃcient andeﬀective maintenance and renewal of the decrepit
existing facilities systematically.
For the reasons stated above, the part of the
Improvement Plan pertaining to construction of dams is
expected to remain in a state of ﬂux for some time into the
future. What will happen in the future is not clear. The ﬂow
of events from the revision of the River Law, however, andthe twists and turns taken place along the way between by
the Committee, the Bureau and the Prefectural Governors
are all indicative of the simmering transformation in the
shape of the governance of the Biwa-Yodo Basin. This
extraordinary sequence of events may be fore-telling thefuture of the public sector decision-making in Japan.

6.6 The Challenges Ahead
The management story of the Lake Biwa-Yodo River Basincan be told in many diﬀerent ways. It is told here as an intricate, but dynamic, history of management challenges

6

involving the upstream Lake Biwa region and the downstream Yodo River region, with factual illustrations of associated policies, programs, and speciﬁc actions for water
resources development, ﬂood control, and environmental
and ecosystem concerns. These factual illustrations are alsointerpreted by the contributing authors, with views reﬂecting their professional backgrounds, as well as their interestsand beliefs regarding the contested and conﬂicting issues.
The geotopographical, climatological, hydrological settings of the Biwa-Yodo Basin have fostered the peculiar geography of the region, with its resulting unique demographic,socioeconomic, and political interactions. Historically, thepressures put on to Lake Biwa and its watershed from thedownstream water users has been enormous because of thelatter’s political, economic, and industrial power. The restrictions on the discharge of Lake Biwa ﬂood water, bothgeophysically and geopolitically, had been causing an insurmountable stress on the relationship between the upstream
and the downstream communities, until a series of physicalinterventions was introduced in the ﬁrst half of the twentiethcentury, including construction of a ﬂood control weir at theoutlet of Lake Biwa. With additional interventions to expand
the role of the weir to accommodate water resources development through LBCDP, the strained relationship between
the upstream and downstream entities seemed to have beenameliorated, at least superﬁcially. The Biwa-Yodo system istoday providing water, ﬂood, and drought mitigations, as wellas environmental and livelihood amenities to the populationof over 18 million living in Shiga and the Keihanshin area,
totaling some 1,200 km2.
The Biwa-Yodo Basin is also characterized by the historic timing of key policy interventions. Whether they
were construction of monumental water control facilities,
development and implementation of instrumental plansand programs, and/or emergence of controversies andconﬂicts, their timings seem to have helped shape lakebasin governance since they relate to the region’s socialand economic proﬁle. As previously discussed, forexample, completion of the Lake Biwa Canal in late nineteenth century led to a miraculous recovery of Kyoto City
from its doomed economy related to limited access towater sources. The installation of Nango Weir in earlytwentieth century also resulted in a dramatic reduction in
the Lake Biwa water level and in the ﬂooding frequency,
allowing Shiga Prefecture to pursue greater economic
opportunities in succeeding decades. LBCDP, a massive,
national-scale public investment project at the helm ofJapanese economic growth, has also brought caused a dramatic change in the management proﬁle of water resources
and ﬂood control, accompanied by the emergence of new
economic geography within the Biwa-Yodo Basin, and in
the entire Keihanshin Region. Thereafter, people and

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6

Evolving History of Lake Biwa and Yodo River Basin Management

industries began to migrate from the densely packed
downstream region to the more spacious upstream region
around Lake Biwa.
The fundamental dynamics of contrasting water management needs, however, remain much the same between
the upstream Lake Biwa region and the downstream Yodo
River region. The former historically being as a resource
provider, while the latter serving historically as a resource
consumer. The underlying intricacy of this fundamental
linkage dynamics resurfaced as a dictating factor in the
evolving process of policy development for the postLBCDP water and environmental management, in relation
to implementation of the Lake Biwa Comprehensive
Conservation Plan (LBCCP), and speciﬁcally its second
phase over the time span of 2011 through 2020, as well as
the recently completed, and controversial, Yodo River
Improvement Plan (YRIP). LBCCP is a plan being developed and implemented by Shiga Prefecture and therefore
touches little on the issues facing the entire Biwa-Yodo

Basin, while YRIP is a plan being developed as a rivermanagement plan, rather than a river basin management
plan, to be implemented as a trans-prefectural plan, legally
to be dictated by the national government.
The overriding issue in the former is whether or not itwill be possible for LBCCP to play a catalytic role in accelerating the lake’s ecosystem integrity when the national
government and the downstream governments and people
consider that they have already fulﬁlled what they were
obliged to do for the lake over the past decades. On theother hand, the overriding issue for the latter is if, and how,the Shiga Prefecture together with the downstream governments may be able to develop a regional institutionalframework for resolving the contentious issues imbeddedin the YRIP. Among the emerging frameworks is a regionally autonomous governance structure for the Biwa-Yodo
Basin, with the national government probably playing
much less prominent role in having “the last say” as having
historically been the case since late nineteenth century.

Topic 21 Lake Biwa Canals
Masayoshi Maehata

There are two adjacent old canals at the south end of
Lake Biwa. These are the ﬁrst and second route of Lake
Biwa Canal, which were built approximately 100 years
ago in the Meiji period to supply water to Kyoto (>Topic
27). As it is called “the water of life for Kyoto citizens,”
the water ﬂowing here at a rate of 20 m3 every second has
been a precious source of drinking water for those living
in Kyoto. While the planning and supervision of signiﬁcant civil engineering works were all entrusted to foreign engineers during this period, this project was
entirely accomplished by Japanese engineers, which wasa memorable achievement at that time. It was a largescaled governmental project comparable to the recent
Lake Biwa Comprehensive Development Project, which
was carried out from 1972 until 1996 at a cost of 1,500
billion yen (Oda 1987). A construction plan for a canalconnecting Lake Biwa to Kyoto seems to have existed as
early as 1800 during the Edo period, for which a pictorial diagram remains as the evidence (Tanabe 1920). The
main reason for the planning of Lake Biwa Canal in the
Meiji period was to restore the declining industries in
the city. Kyoto had ﬂourished for over 1,000 years fromthe time the capital of Japan was established there by
Emperor Kanmu. However, the capital was moved toTokyo in 1869 during the Meiji Restoration. Thereafter,
Kyoto suﬀered a rapid decrease in population and indus-

M. Maehata ()Lake Biwa Museum, 1091 Oroshimo-cho, Kusatsu,
Shiga 525-0001, Japane-mail: maehata@lbm.go.jp

trial activities. Prior to the construction of the canals,
water shortages in the city often aﬀected the irrigation ofagricultural ﬁelds and the operation of water mills. It
also caused serious diﬃculty for the people to obtainwater for drinking and ﬁre-ﬁghting in winter when wells
were dried up (Tanabe 1920).
During the construction of the First Canal, a waterpower station (Keage Water Power Plant) was built at thesame time, which was a technology invented in the UnitedStates. This was the earliest commercial waterpower plantin Japan, which began operating in 1891, being a majorachievement in the industrial history of Japan. The Second
Canal was built with the intent to address the increasing
demand for electricity, and also to settle problems of boththe quality and quantity of drinking water for Kyoto citizens. The outline for these two canals is provided below.
The objectives of the First Canal include: to supply water
for drinking, operation of water mills, generation of electric power, ﬁre-ﬁghting, irrigation, and transportation of
goods by boats, Rate of water ﬂow: 8.35 m3/s, Length:
about 11.0 km, Number of tunnels: 6 (the longest one is2,436 m), Year of completion: 1890. The objectives of theSecond Canal include: To supply water for drinking andgeneration of electric power, Rate of water ﬂow: 15.3 m3/s,
Length: about 7.4 km, Number of tunnels: 1 (the entire
line is composed of a tunnel), Year of completion: 1912

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6

⊡ Fig. 27
Lake Biwa Canals.

Topic 21 Lake Biwa Canals

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