Let’s make Horikawa River Limpid |
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The records of the activities of Horikawa Sen-nin Chosatai 2010 |
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The summary of the result of the investigation in the 9th stage (from April to June, 2011)
The 9th HSC (Horikawa Sen-nin Chosatai) conference, Date : September 10th, 2011 Place : Nagoya Congress Center |
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From secretariat The 9th HSC conference was held at Nagoya Congress Center on September 10th, 2011. The result of the investigation in the 9th stage (from April to June, 2011) is as follows.
⇒Report of the Survey by the Nagoya City
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◎Remarkable points confirmed in the 9th stage |
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1.There were differences between the results of investigation in the Upstream section and Middle section in the second year after the stop of TRWKR (the Transmission of Raw Water from the Kiso River)! |
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During TRWKR (1st stage 〜 6th stage = April, 2007 〜 March, 2010), the effect of TRWKR was confirmed in the Horikawa River (Sanage Bridge 〜 Matsushige Bridge)
The deterioration of the impression of clearness, transparency, COD, ect. was confirmed in the all area between Sanage Bridge and Matsushige Bridge in the past one year after the stop of TRWKR (7th stage = April, 2010 〜 June, 2010). This realized us the good effects of TRWKR again.
In the second year after the stop of TRWKR (9th stage, April, 2011 〜 June, 2011), the deterioration of each indexes was confirmed in the middle section (Asahi Bridge 〜 Matsushige Bridge). But definite deterioration was not confirmed in the upstream section (Sanage Bridge 〜 Johoku Bridge).
Although the further verification is necessary, the cause of this difference can be considered as the following.
1) The quality of the transmission of water from the Shonai River to the Horikawa River (0.3 ton per second) during the 9th stage was considered to be better than that of the 7th stage.
2) Measures for restoration of the Horikawa River implemented by the City of Nagoya might have come into good effects.
・The filtering equipment at Meijo Water Treatment Center (sewage treatment plant) : since May, 2010 ・The Horikawa Ugan Rain-water Reservior for pollution control : since August, 2010
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2. The appearance of the Horikawa River on the day after rainy day. |
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Formerly, it had been thought as a matter of course that the pollution and smell became worse on the day after rainy day, so we had never verified it. But, to our surprise, in the report of survey in the 9th stage, we found that the transparency and impression of clearness of the water on the day after rainy day was better than the day after no-rainy day in the upstream section above the Asahi Bridge.
On the other hand, the transparency and smell on the day after rainy day was worse than the day after no-rain day in the downstream section below Asahi Bridge.
Although it is necessary to make further investigations, the cause of this difference can be thought to be as the following.
1)Horikawa Ugan Rain-water Reservior for pollution control can be thought to be effective in the upstream section above Asahi Bridge.
By the effect of this facility, the rainwater might dilute the pollution and make the river clean.
2) The water pollution of the Shonai River is diluted by rain water and it might have a good influence in the upstream section of the Horikawa River.
On the other hand, the good influence might not be effective in the middle section of the Horikawa River (in the downstream section below Asahi Bridge).
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3. Still in problems in the middle section |
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Although water quality in the upstream section is seemed to be getting improved, there are still problems in the middle section (south section from Asahi Bridge), and effective actions, such as transmission of clear underground water, etc., will be necessary to be considered.
And it must be worth to keep educating citizens about environmental impact through domestic wastewater.
→Distributing leaflets and signature campaign for education activities will be started.
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4. What does people’s first impression depend on? |
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One’s impression like “It is clean.” usually depends on “transparency” of water. One’s impression like “It is dirty.” depends on “color” of water. But when it rained on the previous day, “dirty” impression about the Horikawa River depends on “smells”.
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5. Garbage on the streets along the Horikawa River has increased since the stop of TRWKR |
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Cigarette butts are noticeably scattered around streets.
This can be thought to be caused by these factors as below, and it needs further verification. 1) In the term of TRWKR, some areas of the Horikawa River were visibly clarified. So the citizen might have had hope and been raised their moral. But now, the river got deteriorated again, and their moral seems to have been weakened. 2) While clarification of the Horikawa River went on, people cleaned it up on their own initiative. After TRWKR stopped, their morale might have been shaken and motivation might have been getting lowering.
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6. 70cm is the borderline in transparency of the Horikawa River, to recognize it clear, when people see it. |
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Although some documentary records about this kind of psychological analysis might have already been published, it might be the first case in Japan to verify such feelings of water clearness by the citizens’ efforts of taking the long term and collecting large-scaled data.
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7. Dotted gizzard shad (Konoshiro in Japanese) may die in large number when it rains hard at the spring tide |
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8. The circle of people who love the Horikawa River has been steadily spreading. As of the end of August, 2011, it reached 2,265 groups and 16,862 members (including Horikawa Cheering Groups) |
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We recognized that it is important to spread the circle of people who love the Horikawa River
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9. The total number of reports (internet reports) by Fixed Point Observation Groups reached 2,282 in four years and three months |
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We assume that this is a rare and leading example of such a large scale and a long term survey by citizens.
As we feel proud of those past activities, we also believe that it is important, from now on, to check the effects of the local governments’ policies and pilot projects, to make practical suggestions based on our results, and to keep a dialogue with the administrations.
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The secretariat of HSC offered suggestions of following actions and they were all unanimously approved. So, the HSC, together with the administrations, just took a new step toward reclamation of the Horikawa River. |
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1) We are continuing to propose policies and pilot projects to the administrations based on our survey data and analysis. 2) We need an understanding not only by the people living in the Kiso River basin, but also by the people living in the Nagara River and the Ibi River basins in order to realize the permanent TRWKR.
・To achieve this, it is necessary to deepen exchanges among river basins such as the Nagara River and the Ibi River basins etc., and to let them to learn much about the Horikawa River. And it is also important for us to have a positive attitude to learn about their river basins.
・We are going to make a grass-roots network which helps each other and makes better understanding.
3) We launch the educational campaign of the action, which we can start soon, to take care of our domestic wastewater.
The followings are the documents, which we got from the City of Nagoya, about water transmission from Nakagawa Canal to Horikawa River by Matsushige Pumping Station. |
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The Water Quality of the Horikawa River & Nakagawa Canal (from the annual report 2010 regarding water quality) |
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BOD(annual 75% value) (mg/L) |
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Fiscal year |
2007 |
2008 |
2009 |
2010 |
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Nakagawa Canal |
Matsushige P.S. |
- |
- |
- |
- |
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Tokai Bridge |
8.0 |
8.6 |
6.6 |
8.9 |
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Horikawa River |
Oto Bridge |
4.6 |
3.4 |
4.2 |
5.5 |
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Minatoshin Bridge |
6.6 |
5.2 |
4.2 |
4.9 |
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DO(annual average) (mg/L) |
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Fiscal year |
2007 |
2008 |
2009 |
2010 |
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Nakagawa Canal |
Matsushige P.S. |
5.0 |
4.8 |
4.8 |
7.0 |
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Tokai Bridge |
9.9 |
11 |
11 |
11 |
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Horikawa River |
Oto Bridge |
5.9 |
3.3 |
3.0 |
3.1 |
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Minatoshin Bridge |
6.8 |
6.4 |
6.7 |
6.6 |
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The Pumping to the Horikawa River from the Nakagawa Canal (from the annual report 2010 regarding Matsushige Pumping Station) |
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Per year (annual total) : total of 3 pumps |
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pumping volume |
about 19.5 million m3 |
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pump operating time |
about 1,240 hrs |
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pump operating days |
273 days |
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Per day (daily average) total of 3 pumps |
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average outflow |
about 71 thousand m3 |
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average pump operating time |
about 4.5 hrs |
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Time of pumping to Horikawa River |
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annual total pumping timne |
about 840 hrs |
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average pumping time per day |
about 3 hrs |
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Measures Implemented by the City of Nagoya |
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Why not ask your friends to join us in cleaning the Horikawa River, and make more survey groups!
⇒Recruitment Information (Japanese)
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Let's make the Horikawa beautiful together! |
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Click here to contact us by e-mail. Please include your name and phone number in the e-mail. |
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⇒Link to more of our activities (Japanese)
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