1. Introduction

@Flowing from North to South through the heart of Nagoya city, the Horikawa River is a man-made canal that was excavated during the construction of Nagoya Castle around 400 years ago.  Excavated by order of the feudal lord Fukushima Masanari, its original purpose was to serve as a waterway enabling ships to supply the city with large amounts of goods such as rice, vegetables, fish, and salt.  The Horikawa Riverfs ability to transport goods spurred the development of various industries, and thus the river has for many years been so intimately connected with the lives of the citizens that they have traditionally called it gNagoyafs Mother Riverh.  However, pollution caused a steady degradation in water quality from the beginning of the Showa period in the 1920fs.  By the time this pollution peaked in the 1960fs, the Horikawa had degenerated into a foul, stinking flow choked with sludge.

@In recent years, the City of Nagoya has been working to revitalize the Horikawa River by dredging up the sludge and making repairs to the embankments, and as a result significant progress can be seen in both water clarity as well as maintenance of the river environment and surroundings.  However, due to a number of reasons, a radical improvement in water purity has thus far been elusive.  For example, the Horikawa River lacks its own water source (instead relying on wastewater processed by sewage treatment plants), and so the water tends to stagnate.  Furthermore, at high tide a large volume of eutrophic seawater from Nagoya Bay flows backwards into the river, and it cause bad influence on water quality. So it is necessary to increase the proportion of pure water to prevent these from happening.  For reasons like these, it is the present situation that despite the best efforts of the administration and the sincere wishes of the citizens, a dramatic improvement to the Horikawa River environment has yet to be realized.


2. Civic Activities Supporting Clarification of the Horikawa River

@In May 1999, a coalition of around 30 Lions Clubs in Nagoya carried out a signature campaign to support the early realization of raw water transmission from the Kiso River to the Horikawa River.  They were able to collect nearly 200,000 signatures in under two months.  The appeals of these and other citizensf groups were successful in initiating countless civic activities, such as the planting of 10,000 tulips along the Horikawa River, the Horikawa Photo Contest, a symposium, a convention of elementary school students in support of the river, a clean-up campaign, and many more, demonstrating the citizensf broad support for clarification of the Horikawa River while at the same time realizing concrete progress in cleanup activities.  In response to will of the people, starting from July 2001 the administration has carried out provisional transmission of water (0.3 m3/sec) from the Shonai River to the Horikawa River.


3. The Birth of gThe Horikawa Sen-nin Chosataih (Horikawa River 1000-Citizen Survey Network)

@In order to gauge the effects of this provisional transmission in areas such as water quality improvements, creation of a river culture, and ggreen cityh redevelopment, citizensf groups proposed the creation of a gHorikawa River 1000-Citizen Survey Networkh.  In September 2003, this proposal was officially adopted as an gAll-Japan Urban Renewal Model Enterpriseh, upon which the Nagoya Horikawa Lions Club and other civic groups set out to recruit 1000 citizens for this gHorikawa Sen-nin Chosataih.  During the two-month application period, they exceeded all expectations, receiving applications from 217 individual groups and 2007 citizens in total.  With a broad cross-section of participants young and old, male and female, from elementary, junior high school, and university students to boy scouts, private companies, citizens, and administrators, this endeavor has grown to be a civic social participation experiment of the grandest scale.


4. Nagoya City's Horikawa River Clarification Measures and Organization of the Second Horikawa Sen-nin Chosatai:

(Realizing civic cooperation through gThe Horikawa Sen-nin Chosatai 2005h)

Based on issues proposed during the first Horikawa Sen-nin Chosatai, Nagoya City decided to carry out the following three measures (experiments) aimed at clarification of the Horikawa River.


1.)  Advanced Treatment at the Meijo Sewage Treatment Plant (Short-term Coagulant Addition Experiment)
This one-month experiment investigated the effects on water quality (particularly water clarity) that result from adding a coagulant to the final effluent of the Meijo Sewage Treatment Plant in order to remove suspended solids.  This plant supplies water to the Horikawa River at the rate of 0.6 m3/sec.

2.)  Transmission of Operational Water from Nabeya-Ueno Water Clarification Plant (0.04 m3/sec)
At the water clarification plant, sampling water produced for water quality tests as well as drainage water for backwashing the rapid sand filters has traditionally been reused as raw water, but it has been permanently diverted to the Horikawa River, and the effect upon water quality was investigated.

3.)  Transmission of Shallow Underground Water (0.01 m3/sec)
Underground water drawn from shallow test wells around the upper Horikawa River (in order to inspect the water table, etc.) was discharged into the Horikawa River, and the effect on water quality was investigated.

Figure 2 shows an outline of these three measures.

@To confirm and evaluate these measures from the citizensf point of view, planning and recruitment for this second Survey Network (or, gThe Horikawa Sen-nin Chosatai 2005h) was jointly conducted by the City of Nagoya and the Nagoya Horikawa Lions Club. 

@As the area affected by this gHorikawa Sen-nin Chosatai 2005h was expected to fairly limited, recruitment was targeted at around 50 teams, but in only one month of recruitment in September 2005, the target was surpassed by more than 100%, with 108 teams and a total of 730 people applying.  In October of that year, briefings were conducted, groups were organized, and survey activities began.


6.) Results of the Investigation and Accomplishments of the Horikawa Sen-nin Chosatai 2005
@Investigative activities were conducted from October to December 2005, and because the results of each report were made public through the Internet as soon as they became available, it had already become obvious both to the Chosatai team members and to observers that this experiment had a measurable effect on water quality, with the improvements to sewage processing and transmission of clean water to the Horikawa being clearly vital to cleanup plans for the river.  Mayor Matsubara of Nagoya City made an official announcement of the survey results, publicly acknowledging the observed effects on water quality.  He gave a positive evaluation of the expanding networks to clarify the Horikawa River, and announced progressing to introduce advanced sewage treatment at the Meijo facility on a permanent basis by 2010, in time to commemorate the 400th anniversary of the Horikawa Riverfs excavation.

@In addition, on February 13th, the City of Nagoya announced the start of a new 3-year experiment, Transmission of Raw Water from the Kiso River to the Horikawa River (hereafter referred to as gTRWKRh).  This represented a major step towards fulfilling the citizensf long-awaited dream, embodied in those 200,000 signatures some 7 years prior.  On March 29th, a throng of citizens had gathered in the Kita Ward Office to hear the official announcement of these results, resolving to assemble a third Chosatai when TRWKR was enacted, so that they might advance step by step towards the goal of a clean Horikawa River.


7. TRWKR: The Three-Year Social Experiment and Organization of Horikawa Sen-nin Chosatai 2010

 (Expansion of Civic Movements, Realizing a Partnership between Public and Private, and Spreading Information to the World)

@After learning the results of the Second Chosatai, the governments of Japan and Nagoya spent around a year coordinating with the various groups involved, and on March 27th, 2007, finally announced the start of the three-year TRWKR Social Experiment. Fig.3 shows an outline of it. The Aqueduct for water purification plant and the storm-water drainage are utilized as raw water transmission root. Along with this, formation of the Third Horikawa Sen-nin Chosatai was planned, but now with a much broader scope—to secure the participation of a wide range of participations, an executive committee was formed not only from the Lions Club but from many other civic groups as well.  Recruitment was then initiated under the joint direction of this executive committee and the City of Nagoya.

@Furthermore, in order to further expand the civic network of Horikawa River Lovers, a new gHorikawa Cheering Groupsh program was initiated, by which citizens could freely show their support for the Horikawa River Clarification Program in whatever way they like, without being restricted to the gSurveyh aspect.  During three weeks of recruitment, there were 165 teams totaling 2,262 applicants.  At the present time, there are over 3,000 citizens registered.

The Horikawa Sen-nin Chosatai 2010 began with three programs: gFixed Point Observation Groupsh for the most earnest and dedicated citizens, gFree Survey Groupsh for university students and similarly interested parties, and gHorikawa Cheering Groupsh in which a wide range of individuals and companies can participate as they see fit.  One of these branches, the gFixed Point Observation Groupsh, launched the 1st stage of their activities from April 22nd to June 30th, 2007.  To endure the marathon 3-year stretch of this Third Chosatai, it is being divided into two stages per year, 6 in total, in order to allow for breaks and to keep participants sharp.  In addition, this enables step-up improvements – problems encountered in one stage can be translated into process improvements for the next.













Return to Top of This Page

Return to Main Page