Horikawa Sen-nin Chosatai (HSC)
(Horikawa River Thousand-Citizen Survey Network 2010)
Hiroshi Hattori1, Tomonori Yamamoto2, and Yasuhiro Miwa3
1Secretariat, Horikawa Sen-nin Chosatai 2010
Marunouchi, Naka-ku, Nagoya, 460-0002, Japan, email: firstname.lastname@example.org
2Engineer, Horikawa River General Development
Office, Greenification & Public Works
Bureau, Nagoya City
Sannomaru, Naka-ku, Nagoya, 460-8508, Japan, email: email@example.com
3Engineer, Sewerage Planning Division, Waterworks
& Sewerage Bureau, Nagoya City
Sannomaru, Naka-ku, Nagoya, 460-8508, Japan, email: firstname.lastname@example.org
1. Introduction: Nagoya's Mother River
The Horikawa River, a first-grade river approximately 16 km
in length, flows north to south through the
central part of Nagoya City. Some 400 years ago, when Nagoya Castle was built, this man-made river was constructed
as a water channel for transporting castle
construction materials such as timber and
Because the Horikawa lacked a natural water
source, it tended to stagnate. During the
period of high economic growth in 1960s,
the river became increasingly contaminated
due to wastewater from factories and residences.
The people of Nagoya had honored the Horikawa for more than 300
years as the City's “mother river.” Now,
however, it had been transformed into a sludgy,
smelly and filthy river, and buildings began
to be built with their backs to the river.
2. Administrative Moves and Citizens' Growing
In 1985, the national government announced
that the “My Town, My River Development
Project” would first deal with the Horikawa River. This decision accelerated Nagoya City's project to full scale toward river revitalization.
Since as a result of these efforts the Horikawa
gradually became cleaner, citizens had a
growing interest in positive action and revitalizing
the river. Cleaning and learning activities
were going on everywhere.
In 1999, the citizen-led signature-gathering
campaign "Clean Up the Horikawa!"
collected 200,000 signatures in only one
month. Citizens' interest in clarifying the
river grew rapidly.
3. The First Horikawa Sen-nin Chosatai
In 2003, the citizen-proposed program of
the “Horikawa Sen-nin Chosatai (HSC) (Horikawa
River Thousand-Citizen Survey Network)”
was adopted as “All-Japan Urban Renewal
Model Enterprise” and received a subsidy
from the national government.
Since the Horikawa lacks a natural water
source, water is transmitted at a rate of
0.3m3/s from the Shonai River, which runs through the northern part of
Nagoya City, in order to maintain the Horikawa's aquatic
The First HSC was organized to allow many
citizens to take part in surveying the changes
in the Horikawa’s water quality and waterfront
environment that resulted from the temporary
increase in water volume.
During its two-month duration, 2007 persons
(217 groups) applied for participation, far
beyond expectations. The survey by citizens
grew on an unprecedented scale.
4. Survey Results and Problems of the Horikawa River, Presented by the First HSC
In 2004, the First Horikawa Sen-nin Chosatai
conducted surveys for four months and held
a meeting to announce the results. The meeting
pointed out that the Horikawa had various
problems from citizens' point of view.
Specifically, many citizens participating
in the HSC were shocked by the fact that
there was no noticeable water quality improvement
resulting from a simple increase in water
volume from the Shonai River into the Horikawa River. Then the participants became aware of the
need for a water quality improvement campaign
throughout the entire basin area, including
the upstream region, as well as for citizen-level
exchanges and cooperation.
Moreover, participating citizens shared awareness
that the river would remain unclean unless
improvements were made on treated wastewater
from sewage treatment plants, because such
discharge is a substantial water source of
the Horikawa River.
5. Municipal Policies in Nagoya and Formation of the Second HSC
In light of problems revealed by the First
HSC, moves were initiated on the administrative
side. In 2005, the municipal government of
Nagoya decided to implement a social experiment
aimed at improving the quality of the water
source by conducting an advanced treatment
test for one month at the Meijo Sewage Treatment
They also decided to verify the effects of
the test, from citizens' perspective, via
the Second HSC (HSC2005). The three-month
survey conducted by citizens revealed that
the quality of water source improvement test,
including advanced sewage treatment, was
highly effective for clarifying the Horikawa River.
6. Toward the Next Stage
On the basis of test results, the municipal
government of Nagoya announced a plan to consider implementing
permanent advanced treatment at the Meijo
Sewage Treatment Plant in 2010. This was
followed by the announcement of a social
experiment to transmit water from the Kiso River to the Horikawa River, a dream of the people of Nagoya.
Through the activities of the First HSC,
citizens pointed out the problems of the
Horikawa. In the light of those problems,
the municipal government conducted the quality
of water source improvement testing. The
test results were verified by the second
HSC, which was followed by the municipal
government's decision to test taking water
from the Kiso River and carrying out sewage treatment plant
7. Third HSC Activities
A test of transmitting water from the Kiso River to the Horikawa River at a rate of 0.4 m3/s commenced in March 2007, gaining the understanding
of stakeholders, including people in the
Kiso basin area. At the same time, the third
HSC (HSC 2010) began its activities.
There are now up to 200 reports from the
HSC each month. Citizens who love the Horikawa
are watching the river all the time, from
all aspects. Their reports, containing photos,
are posted on web-pages in real time.
Citizens' reports thus far reveal steady
improvement in the clarity of the Horikawa
since the commencement of water transmission
from the Kiso River. These reports indicate signs of revitalization
of the self-cleansing capabilities of the
Horikawa, changes made possible by the oxygen-rich
clean water of the Kiso River.
Citizens take the lead in the vigorous activities
of the HSC, making the best use of their
network. Their lively activities make us
feel that this is a viable form of organization
for the new age of the 21st century.
Clarification of the Horikawa River has been a long-sought goal of, and a tough
challenge for, the citizens of Nagoya. However, the resident-administration partnership
of the HSC has precisely met the challenge.
The network's activities suggest the possibility
of revitalizing the limpid flow of the Horikawa,
and offer hope and assurance to citizens.