Horikawa Sen-nin Chosatai 2010th

Summary meeting for the 19 stage

The ｓecretariat of Horikawa Sen-nin Chosatai 2010
Sep.3th.2016

Place：
Nagoya Urban InstituteConference room (11th floor)

Photos：The secretariat of
Goyousui-ato-gaien-aigokai
Survey Group1

Horikawa Sen-nin Chosatai 2010
〜Transmission of Raw Water from
Kiso Riveｒ〜
1.Purpose
To verify the clarification effects of TRWKR with
Citizens
The formation of HSC (April 22nd, 2007)(1)Develop to new clarifying measures
With a viewpoint and a sence of citizens, the survey of(2)Asses the influence on an ecosystem
the clarification effect of TRWKR started(3)Sustain and enhance citizens activities.
(4)Develop citizens awareness in the entire
Horikawa River basin
2.Water source and Volume of transmissionof raw water(1)Water Source : Kiso River(2)Volume of transmisission of raw water:Maximum 0.4 m3/s
3.Pilot project period(1)Evaluation and Survey term : About 5 years ■ The survey from a viewpoint and a sence of citizens＊Clearness ＊Transparency ＊Color ＊Bubble ＊Smell（from Apr.2007 to Mar.2012）(Including the term of follow-up survey and ＊Garbage ＊ Living things ,etc
evaluation after the stop of TRWKR)(2)TRWKR period : about 3years(from Apr.22nd, 2007 to Mar.22nd, 2010)■Increase of Transmisson Volume
from the Shonai River(additional pilot project）(1)Water Source : Shonai River(2)Transmission Usual 0.4m3/sec (maxium 0.7m3/sec)(3)Experiment Period ：Oct.1st-Dec.31st ,2010(4)Period of Increased Transmision
Volume :Oct .5th-Nov.2nd ,2010

The first Nagoya City Environmental practice Prize February.2012
Branch of contribution for Regional Environment Development
Award for excellence３

Transmission of Raw Water from Kiso River
3 years from April 22nd, 2007（Stopped on March 22nd,2010）
To verify the clarification effects of TRWKR
Surveys during TRWKR period :April 2007 〜 March 2010
Surveys after the stop of TRWKR period :April 2010 〜 March 2012

Horikawa Sen-nin Chosatai
April 2007〜March 2012
■ Fixed Point Observation Groups
Surveying effects of TRWKR■ Free Survey Groups
Researching Horikawa River by free themes■ Horikawa Cheering Groups
Cheering clarification of Horikawa

The survey from aviewpoint and asence of citizensTs of

Results of pilot project ( Clarification
effects of TRWKR)■ It was confirmed that the water quality tended to improve
during TRWKR between Sanage Bridge and Matsushige
Bridge.
■ Network of citizens who wish for clarification andrestoration of Horikawa River expanded.
■ Citizens awareness of cleaning of the river wasdeveloped■ Role of the survey group(Conclusions of Summary Meeting for the 10th Stage)① More surveys should be implemented.
・Continuity of investigation, clarification of
the situation of the river, identification of
cause of pollution in the river, are needed.
・We improve our plan and take action
against the pollution.
・After that, citizens and public
administration do what is possible toclean the river.
②There are many things that citizens cando.
・We expand our partners who love
Horikawa River and hope TRWKR again.
・We deepen exchanges with people livingin the basin of Kiso, Nagara, and Ibi River.
・We check the effects of pollution
removal from domestic wastewater andimplement it in each house.

４Horikawa Sen-nin Chosatai was commended
by Minister of Land, Infrastructure and Transportation
Date : 1st Aug. 2016

Place : Science Hall in Science Museum

Water Resource Contributor Awards
It is awarded to group and individual contributing continuously to administrative promotion indevelopment and utilization of water resource.

5

Horikawa Sen-nin Chosatai reported to Mayer of Nagoya City
that they were commended by Minister of MLIT
Date : 2nd Aug. 2016

Place : Nagoya City Hall

Reference: Chunichi Newspaper
7th Aug. 2016, morning edition

Horikawa Sen-nin Chosatai visited the mayor
of Nagoya City, and reported that they werecommended by Minister of Land, Infrastructure
and Transportation.
The mayor said, I would like to improve theenvironment of Nagoya castle and Horikawa
River integrally and to make the river clean
enough to swim all the way to Nagoya castle .

Reference: Asahi Newspaper
4th Aug. 2016, morning edition

6

Water Environment of Horikawa River
Area of basin: 51.9km2
Length: 16.2km

Change in temperature, precipitationand hours of sunshine
Cause of breeding of
pphytoplankton,
nitorogen andphosphorus areincluded inwastewater fromhouses, factories andstores.

Kiso River is our water source.

The primary cause of water pollution is wastewater from houses, factories, and stores.
Wastewater is discharged after treatment in wastewater treatment plant.
●●●

After heavy rain, wastewater isdischarged without treatment.

●●●

●●●

●●●

Tide Gate▼High Tide●●● ●●●●●●●●●

Wastewater
Treatment Plant

Shonai River
Privisional raw watertransmission: 0.3m3/s

Sanage Bridge▼

Horikawa River▲
Motoiri Sluiceway

Difference of water level is more than 2m between high tideIt has looked like red▼Ebb Tide and ebb tide.
tide or blue tide.
In Nagoya Port andWater level, direction of current and velocity are changed, by tide.
downstream of
Nagoya Port
Horikawa, it is said
Rising
Shimizu wakuwaku-suithat phytoplankton
Ise Bay
Groundwater, etc
does over breedingand extinction, so
water basin is polluted
Red TideBlue Tide

Sludge rises and floats.
Floating Sludge

Raised Sludge

7

Observation method at fixed-point
Measurement of Transparency

Measurement of COD
COD: Chemical Oxygen Demand

Transparency
Meter
100cm

Photo: Shinko Survey Group

What is yourimpression of…
Clearness? Transparency?
Color? Bubbles?
Smell? Garbage?
Living things?

Yuri-no-kai Survey Group
Photo: Goyosui-ato-gaien-aigokai
Survey Group

This is an index of watercontamination used for sea, lakes, andmarshes.
It is an oxygen consumption requiredfor oxidation of organic mattersdissolved in ample water.
The higher COD, the more it iscontaminated.

COD Pack Test

Photo: Goyosui-ato-gaien-aigokai
Survey Group8

Number of Participants ofHorikawa Sen-nin Chosatai

Investigation spots(Horikawa Sen-nin Chosatai started
accepting participation on 26th Mar.2007)
Network of citizens who wish for clarification
and restoration of Horikawa River is growing.

Start

Now

22nd Apr.2007

3rd Sep.2016

Fixed Point
Observation
Groups55 groups
497persons

99 groups
1,006persons

Free Survey
Groups

22 groups
234persons

40 groups
650persons

Horikawa
Cheering
Groups

88 groups
1,531persons

2,577 groups
51,756persons

Total

165 groups
2,262persons

2,716 groups
53,412persons

9Number of Participants ofHorikawa Sen-nin Chosatai

September 3rd 201610

Survey Period and Number of Reports
With TRWKR

Utilization ofshallow groundwater
At upstream ofKitashimizu bridge

Introduction of advanced
water treatment at the Meijo
Water Treatment Center
In-service of Horikawa
Ugan Rain-Water Reservoir
for pollution control

Increase of Transmission
Volume from the Shonai River

Utilization of reclamedwastewater from
Moriyama
Water Treatment Center
At upstream of
Seko Bridge

At upstream of
Sanage Bridge

Sand Covering
At upstream of
Shiga Bridge

At upstream of
Nakatodo Bridge

total

Survey Period
1st stage
Spring〜Early summer/Apr.22nd〜Jun.30th.2007
interval
Jul.1st〜Sep.7th.2007
2nd stage
Autumn〜Early Winter/Sep.8th〜Dec.16th.2007
interval
Dec.17th.2007〜Mar.31st.2008
3rd stage
Spring〜Early summer/Apr.1st〜Jun.30th.2008
interval
Jul.1st〜Sep.27th.2008
4th stage
Autumn〜Early Winter/Sep.28th〜Dec.16th.2008
interval
Dec.17th.2008〜Mar.31st.2009
5th stage
Spring〜Early summer/Apr.1st〜Jun.30th.2009
interval
Jul.1st〜Sep.26th.2009
6th stage
Autumn〜Early Winter/Sep.27th〜Dec.16th.2009
interval
Dec.17th.2009〜Mar.31st.2010
7th stage
Spring〜Early summer/Apr.1st〜Jun.30th.2010
interval
Jul.1st〜Sep.11th.2010
8th stage
Autumn〜Early Winter/Sep.12th〜Dec.17th.2010
interval
Dec.18th.2010〜Mar.31st.2011
9th stage
Spring〜Early summer/Apr.1st〜Jun.30th.2011
interval
Jul.1st〜Sep.10th.2011
10th stage
Autumn〜Early Winter/Sep.11th〜Dec.16th.2011
interval
Dec.17th.2011〜Mar.31st.2012
11th stage
Spring〜Early summer/Apr.1st〜Jun.30th.2012
interval
Jul.1st〜Sep.21th.2012
12th stage
Autumn〜Early Winter/Sep.22th〜Dec.16th.2012
interval
Dec.17th.2012〜Mar.31st.2013
13th stage
Spring〜Early summer/Apr.1st〜Jun.30th.2013
interval
Jul.1st〜Sep.28th.2013
14th stage
Autumn〜Early Winter/Sep.29th〜Dec.17th.2013
interval
Dec.18th.2013〜Mar.31st.2014
15th stage
Spring〜Early summer/Apr.1st〜Jun.30th.2014
interval
Jul.1st〜Sep.28th.2014
16th stage
Autumn〜Early Winter/Sep.29th〜Dec.16th.2014
interval
Dec.17th.2014〜Mar.31st.2015
17th stage
Spring〜Early summer/Apr.1st〜Jun.30th.2015
interval
Jul.1st〜Sep.19th.2015
18th stage
Autumn〜Early Winter/Sep.20th〜Dec.16th.2015
interval
Dec.17th.2015〜Mar.31st.2016
19th stage
Spring〜Early summer/Apr.1st〜Jun.30th.2016

reports
258
134
383
103
245
64
152
100
145
54
120
81
111
44
104
72
112
42
133
77
148
60
139
92
145
70
113
79
133
91
99
107
113
81
126
91
127
4,348

11

Number of Reports
5000
at the end of 19th stage
４，３４８

4500

3500
3000
2500
2000
1500

About 400 reports every year

1000
500

19th stage

18th stage

17th stage

16th stage

15th stage

14th stage

13th stage

12th stage

11th stage

10th stage

9th stage

8th stage

7th stage

6th stage

5th stage

4th stage

3rd stage

2nd stage

0

1st stage

Number of Survey Result Reports

4000

The total number of survey reports is 4,348 by the end of the 19th stage.
On average, it is about 400 reports every year.
A lot of citizens survey the real state of water environment of Horikawa
River continually from a viewpoint and a sense of citizens.

12

４．Main Measures for Water Quality Improvement
FY2007

Measures

FY2008

1st.

FY20093st.
2st.

FY2010

5st.
4st.

FY2011

7st.
6st.

FY2012

9st.
8st.

11st.
10st.

FY2013

FY2014

13st.

15st.

12st.

14st.

16st.

FY2015FY2016

17st.

19st.
18st.

3

With TRWKR(0.4m /s)
Build deepand shallow
zones
Makingshallowand deepb/w Kurokawa No.1Brdg. 〜Meoto Brdg.

(Improvement of self-purification function andwater environment)

Downstream areaof Kurokawa No.2 Brdg.

Upstream area of Kurokawa No.2 Brdg.

Upstream areaof Kurokawa No.2 Brdg.

Increase of raw water transmission from Shonai
3River(＋0.4m /s)
Upstream area of Tsujie Brdg.0.01m3/s(H16)
Upstream area of Kizune Brdg.0.01m3/s(H17)groundwater
Utilization of shallow grandwater

Upstream area of
Upstream area of
Upstream area of
Seko Brdg. 0.01m3/s Sanage Brdg. 0.01m3/s Siga Brdg. 0.01m3/s

3(0.0405m /s)

Upstream area of
Nakatsuchido Brdg.
0.01m3/s

Shimizu wakuwaku water0.0005m3/s(FY2008)

Experiment of sandcoveringsand for water purification
covering
b/w Gojo Brdg.-Naka Brdg.
（water's edge along both banks）
Introduction of Advanced water treatment at Meijo
atthe Treatment
Meijo Water
Treatment Center
Water
CenterIn-service of Horikawa Ugan Rain-water Reservoir
for pollution control
Utilization of reclaimed wastewater at Moriyama
3 (0.046㎥/s)
at
the Moriyama
Water
Treatment Center
/s)
Water
Treatment
Center(0.046m

Newly launched facilities after the stop of TRWKR■Treated water quality improvement
For improvement of water quality which isdischarging into Horikawa River, treated water at
the Meijo Water Treatment Center is filteredadditionally.

Advanced water treatment
at the Meijo Water Treatment Center
Solution : conventional activated sludge
process and rapid filtration
Launch : May. 2010

■Improvement of the combined sewer system
High-polluted first flash rain water is stored
temporarily to reduce the frequency of sewer
outlet overflow.

Horikawa Ugan Rain-water
Reservoir for pollution control
Capacity : 13,000m3
Coverage Area : 633ha
Launch : Sep. 2010

Improvement of
the combined sewer system
Construction of
the storage facilities
LegendCompleted
Under construction

13

Newly launched facilities after the stop of TRWKR

MakingAdditional Water Sources
Utilization of Reclaimed Wastewater（exc. winter）

Moriyama Water
Treatment Center

By using reclaimed wastewater treated with themembrane filtration at Moriyama Water Treatment
Center, up to 4000m3/day is conducted
into Horikawa River.

通水開始
平成23年8月
Start to conduct
in Aug. 2011

Shonai Irrigation

Discharging point
into Horikawa River※ Reclaimed wastewater is conductedduring irrigation season（Apr.-Oct.）

Horikawa
River

Reference： The
18th Horikawa Sen-nin
Chosatai conference
参考資料：第18回
堀川１０００人調査隊会議

14■ Making Shallow and Deep
Common indian kingfisher, little egret, turtle
Carp, Crucian carp,
Hemibarbus barbus
Goby minnow

Pale chubAmur goby

Young palechub

Shrimp, crab, aquatic insect

Stone
masonry

Various living things
come to this place forgrowing and breeding.
However, a lot of carps
and black bass alsocome there to eat small
fishes and shrimps. We
need to take it into
consideration and avoid
feeding carps.

Waterside
Common Indian
Kingfisher,
Black-crawnednight heron

Pollution（organic substance, Nitrogen, phosphorus, etc）

Small fishes, shrimps and insects eat algae and microbes.

Reeves turtle
SliderCarp, Hemibarbus barbus,
Catfish, Black buss, Bluegill
Northern snake head

■ The Self-cleansing Action by Food Chain

Algae and microbes are spread by pollution.

In WaterPrawns andJapanese mitten
crabs migrate
between rivers andthe sea.

Big fishes and birds eat small fishes and water-dwelling insects.

Crucian carp, Pale chub, Goby
minnow, Amur goby, Mosquitofish

Palaemon adspersus, Prawn,
Japanese mitten crab, Aquatic
insectDownstream area of Kurokawa No.2 Brdg.
Completed in 2012

Upstream area of Kurokawa No.1 Brdg. Completed in 2010

Various environments are maintained in Horikawa River by
being building deep and shallow zones and changing according
to environments.
Pale chubs eat algae on stones.
Fishes spawn at sand gravel.
Small fishes and shrimps are eaten
by too many carps.

Photo by The secretariat Jul, 2016

Downstream area of Ruriko Brdg.
Completed in Feb, 201615

Purification Experiment by Sand Covering
Started in Feb. 2015

Making Additional Water Sources(Using shallow ground water)
A well at upstream area of Nakatsuchido Brdg.
Started in Mar. 201616

５．Report of the 19th stage survey
5.1. Introduction 〜Column〜〜Column〜 For clarification and regeneration of Horikawa River
Horikawa Sen-nin Chosatai was established at 22th April, 2007, as a place for citizens activities, Fixed Point Observation
Group, Free Survey Group and Support group, for clarification and regeneration of Horikawa River.
Fixed Point Observation Group examines Horikawa River with TRWKR, from a viewpoint and a sense of citizen for, confirming theclarification effect, water quality and elucidation of cause of pollution. Free Survey Group study Horikawa River from various
view point. Support group supports clarification and regeneration of Horikawa River in various ways. Then the three groups wish
for clarification and regeneration of Horikawa River, and work together in a Large network.
Currently(3rd September, 2016) there are a total of 2,716 groups and 53,412 persons in the research team, 99 groups in
Fixed Point Observation Group, 40 groups in Free Survey Group and 2,577 groups in Support group. At the time of launch
there was 165 groups and 2,262 persons. It shows that the network of citizens wishing for clarification and regeneration ofHorikawa River has expanded greatly.
Fixed Point Observation Group observed 4,348 times from 1st stage to 19th stage. So far, we found that the state of the waterchanged from moment to moment due to the influence of the tides, at the downstream from the Sanage Bridge. And we canfound that a lot of observation results from the Fixed Point Observation Group can capture the average state of water quality ofHorikawa River by citizen s point of view and sense, and understand the tendency of the change.
〜Social experiment of the clarification of Horikawa River Confirmation of clarification effect of TRWKR from 2007 April to2012 March 〜
We confirmed that water quality between Sanage Bridge to Matsushige Bridge had been improved by TRWKR(0.4m3/sec.) infive years. And in this period, we confirmed that the garbage (Artificial garbage: plastic type garbage etc.)reduced. It seems
that the consciousness of the citizen changed, such as the cleaning activity became active.

【Five years summary】■We confirmed clarification effect of TRWKR■Network of citizens wishing for clarification and regeneration of Horikawa River has expanded greatly■Consciousness of the citizen changed, such as the action of the cleaning activity became active.

17

１. Weather Condition in 19th stage
Warm air flow from south brought the highest temperature since 1st stage. And continuous short cyclic heavy
rain caused the most precipitation in April from 1st to 19th stage. On the other hand, the rainy season began inJune 4th, as average start time.
Characteristic of 19th stage: high temperature and continuous short cyclic heavy rain
２. Survey Result of 19th stage
Impression of water clearness from Sanage bridge to Oseko bridge in 19th stage generally got worse from 17th
stage. Negative evaluations about smells increased, positive ones about transparency decreased, and sludge often
made the color grey green. They showed the water cleanness of river bottom of Horikawa river worsen because ofhigh temperature and continuous short cyclic heavy rain. However the impression got better from Sanage bridge toJohoku bridge area.
３．Change after stopping TRWKR
After stopping TRWKR(H22 March), introduction of Advanced water treatment at the Meijo Water Treatment
Center(H22 May), in-service of the Horikawa Ugan Rain-water Reservoir for pollution control(H22 September),and utilization of reclaimed wastewater at Moriyama Water Treatment Center(0.046m3/s H23 August) werelaunched.
Furthermore, experiment of covering sand for water purification from Gojo bridge to Naka bridge(H27 February)
started and utilization of shallow ground water from wells supplied more water source.
Water clearness of Horikawa river got worse after stopping TRWKR, but slight trend of improvement is observed
from upper stream except temporal weather effect. It should be brought by citizen s awareness and various
measures for water quality improvement.
Though water quality level is not enough for citizen s acceptable clearness and transparency(70cm,), especiallyin spring- early summer stage.
Continuous survey based on fixed-point observation and general survey on high tide in Spring is necessary to
elucidate mechanism of worse water quality in Spring-early Summer stage, and we need installation of more
improving measures.

18

(Reference)(Survey section)

Impression of
Water Clearness
Ratio of Clean Ordinary(see p.33)

slightly improving
With TRWKR
improvingworsened
after stopping TRWKR

dirty

Change oftransparency(see p.44)

With TRWKR
improvingworsened
after stopping TRWKR

cleanslightly improving

19

（Reference）

Change of COD(see p.50)

Change in occurrenceof smell
Total ratio of terrible smell,bad smell and smell(see p.62)

With TRWKR
improvingWith TRWKR
keeping or improving

slightly worsened
after stopping TRWKR

worsened
after stopping TRWKR

slightly improving

slightly improving
Except weather effect20

４．Influence of Rain
We analyzed survey data of the days that it rained or not on the previous day(No TRWKR).
①Impression of Clearness
Impression of Clearness got better when it rains on the previous day above the Asahi Bridge and worse when
does not rain on the previous day below the Asahi Bridege. When it rained on the previous day, evaluation valueof smell increased, and evaluation value for the color decreased. Evaluation value of garbage increased below
Johoku Bridge.
②Transparency
Transparency got lower when it rained on the previous day. It was the lowest between Johoku Bridge andMatsushige Bridge.
③ＣＯＤ
COD got lower when it rained on the previous day between Sanage Bridge and Johoku Bridge. No deffrence
was seen about COD whichever it rained or not, below Johoku Bridge.
④Colors
Ratio of milky was bigger when it rained on the previous day.
Impression of Clearness Comparison of rain with no rain on the previous day Sanage Bridge〜Oseko Bridge
April 2010(the 7th stage) - March 2016
Rain and No rain on the previous day
No rain on the day

No TRWKR

Matsushige Bridge

Kameya Bridge

Johoku Bridge

Asahi Bridge

90%

5%

Percentage of Bubbles(%)

67％

71％

50%

36%

44%

30%
20%

90%

19%
12%

60%

40%

100%

2%
8%

16%

80%
70%

[1]Dirty[3]Ordinary[5]CleanDirty〜
Slightly dirty
31%

10%

27%

0%

4%
20%

80%

Percentage of bubbles(%)

100%

Kameya Brg.〜Matsushige Brg.

[4]Slightly clean[2]Slightly dirty

70%
60%
50%
40%
30%
20%
10%

Sample309

Rain on theprevious day
No rain on tne day
Sample48[1]Dirty[3]Ordinary[5]Clean
100%

3%
11%

90%

13%
18%

58％
30%

73％
52%

Dirty〜
Slightly dirty
28%

21%

0%
No rain on the day
and the previous da

Matsushige Brg.〜Asahi Brg.

[2]Slightly dirty[4]Slightly clean

No rain on the day
and the previous daSample303

Rain on theprevious day
No rain on tne day
Sample38

80%
70%
60%
50%

2%
9%
13%

76％
39%

5%

100%
90%

2%
11%

80%

17%

38%

30%

Dirty〜
Slightly dirty

20%

37%

40%

[1]Dirty[3]Ordinary[5]Clean

14%

81％

43%

10%

70%
60%

40%
30%
20%
10%

No rain on the day
and the previous daSample574

Rain on theprevious day
No rain on tne day
Sample111

Impression of clearness gets worse
when it rained on the previous day

100%

10%

54%

42％
Dirty〜35%
Slightly dirty

No rain on the day
and the previous daSample152

7%
Rain on theprevious day
No rain on tne day
Sample29[2]Slightly dirty[4]Slightly clean

5%

5%

22%

26%

90%
80%

31%

17%

16%

[1]Dirty[3]Ordinary[5]Clean[2]Slightly dirty[4]Slightly clean

70％

50%

0%

0%

Johoku Brg.〜Sanage Brg.

Asahi Brg. 〜Johoku Brg.

[2]Slightly dirty[4]Slightly clean

Percentage of bubbles(%)[5]Clean[3]Ordinary[1]Dirty

Percentage of bubbles(%)

Ooseko Brg.〜Oseko Brg.

Sanage Bridge

Meijo Water Treatment Center

Shin-Horikawa River confluence

Percentage of bubbles(%)

Oseko Bridge

70%

14%

12%

60%
50%

59％

40%

39%

36%

20%

Dirty〜
Slightly dirty

10%

20%

21%

No rain on the day
and the previous daRain on theprevious day
No rain on tne day
Sample42

30%

57％

0%

Sample283

Impression of clearness gets better
when it rained on the previous day

21Comparison of rain and No rain on the previous day

Sanage Bridge - Oseko Bridge

April 2010(the 7th stage)〜March 2016
No TRWKR
Oseko Bridge

Rain and No rain on the previous day

Kameya Bridge

Matsushige Bridge

No rain on the day

Asahi Bridge

Johoku Bridge

Sanage Bridge

Meijo Water Treatment Center

Shin-Horikawa River confluence

It was the lowest between Johoku Bridge andMatsushige Bridge when it rained on the previous day.
acceptable over 70cm for citizens

Transparency

COD got the lowet when it rained on the previous day between
Sanage Bridge and Johoku Bridge.

COD

22

５．Living things
Kinds of gobies came back in the river in March, about a month earlier than usual. It maybe because it was
warmer than usual. In addition, lots of little mullets came back in the river in 19th stage.
Birds of prey, which is the top of food chain in the Horikawa basin, were observed after the 18th stage. We
can realize the diversification of an ecological system.
However, lots of gizzard shad died in June. We thought the mass death of fish was caused by the lack ofoxygen. We analyzed records of the mass death in the past and set up two hypotheses according to relation
among seasons (temperature), tide and rainfall.
We have to continue observing and recording living things to make clear the mechanism between the lack ofoxygen and the mass death of fish.
（Hypothesis 1） high tide from Spring to Summer (large change of tidal level)・・・hypothesis in the past
（Hypothesis 2） low tide from Spring to Summer(small change of tidal level)・・・new hypothesis
temperature rises → tidal level doesn t change much and river water doesn t replace muchoxygen supply decreases and it s tend to become lack of oxygen
From Spring to Summer, when thetemperature is tend to rises, decompositionof organic matter activated and oxygen in
the water is consumed much.

＋

more organic
matter inflows
with rainfall＋

Especially when tidal level changes little bit
and water replaces little bit , oxygen supply
decreases and oxygen in the water becomesvery poor.

６．Water quality of Shin-Horikawa River
We had made 196 surveys by the end of 19th stage, 100 surveys just during 19th stage, at
Shin-Horikawa. Because these are not enough data, we analyzed the situation of ShinHorikakwa by all those data including with rain on the day and the previous day.
It has become clear that impression of water clearness between the Maizuru Bridge andthe Horagai Bridge in the upstream section is especially bad, and it has also become clearthat change of transparency , COD , Bubbles and Smell are especially bad in the
upstream section.
Secretariat considers that the basin could become in a situation like blue tide by judging
from Smell and Colors .
We have to continue surveying at more points and collecting data to make clear the situationof water quality at Shin-Horikawa from the citizen s point of view.

at the Maizuru Bridge
to upstream

at the Utsugi Bridge
to downstream

23

７．Spring Massive Research（April 6th 2016）higher temperature and more precipitation before
the researching day and 40.5mm precipitation on
the previous day■Summary of the impression of water clearness
We can see the difference between upper andlower of Sumiyoshi Bridge(1) Upstream of Sumiyoshi Bridge①mostly slightly dirty - dirty based on
the color②raised sludge made the color dark grey
when ebb tide
③ bubbles , smell like rotten eggs andgetting milky at ebb tide. We think thatlowered pressure made sulfide released
into water from riverbed. This is an
important clue to understand Horikawa
River getting milky after rain.
④Transparency was under 50cm （over70cm is acceptable for people)(2)Downstream of Sumiyoshi Bridge①Some reported ordinary - clean . The
impression of water clearness was a little
better than that of upstream.
②Transparency was over 50cm.
③ bubbles were seen at ebb tide andcolor was grey green and dark green.
Sludge smell was sensed.

■Gathering and moving of garbage①Garbage gathered in front of Matsushige Rock Gateduring ebb tide. And they were pushed up to Naka
Bridge when high tide. Garbage make impression
worse. This is an important clue how to remove themand how not to let them gather.
②Garbage was reported at high tide around Goryo bridge
which is in the downstream of Sumiyoshi bridge.
We need to research it from now on.

(see 96)

24

尾
頭
橋

古
渡
橋

山
王
橋

日
置
橋

岩
井
橋

Matsushige
Rock Gate

garbage？

garbage

松
重
橋

熱
大
田
瀬 白 御 記子 鳥 陵 念橋 橋 橋 橋

旗
屋
橋

瓶
屋
橋

古
渡
橋

山
王
橋

松
重
橋

~ ebb tide ~天王崎橋garbage

日
置
橋

岩
井
橋

新
洲洲
崎崎
橋橋

天
王
崎
橋

錦
橋

伝
馬桜
橋橋

五
条
橋

hollow part

納
屋
橋

錦
橋

伝
馬桜
橋橋

五
条
橋

garbagegarbageebb tide

納屋
橋~ high tide ~Nakagawa
Canal
尾
頭
橋

新
洲洲
崎崎
橋橋

Naka Brdg

Nakagawa
Canal

Naka Brdg

瓶
屋
橋

旗
屋
橋

Sumiyoshi Brdg

junction of
Shin-Horikawa River

？

熱
田
大
瀬 白 御 記子 鳥 陵 念橋 橋 橋 橋Sumiyoshi Brdg

（Our Hypothesis） Gathering and Moving of Garbage

high tide
Naka
BridgeMatsushige Rock Gate

25

８．Experiment of Horikawa River clarification by sand cover etc.（start in Feb, 2015)
Shorebirds searching for food on the river bed with covering sand on the water
surface were seen during low tide in the spring tide.
Assuming that many kinds of living things which shorebirds eat inhabit, improvementof biological clarification by food chain can be expected.

Hint for the river environment which hardly pile sludge?
Sludge was seen on the river bed with covering sand on left bank in downstreamof Gojo Bridge, while sand particles were seen near the bank. Seeing there from
opposite bank, it shows us that these area is a little higher than other area.
This may be the hint to consider the water environment (including the form of riverbed) which prevents sludge to accumulate.

Improvement of natural purification
by food chain is expected.
What kind of living things live andthrive at the sand-covered area?

Birds(river edge)
・Eurasian sparrowhawk
・water wagtail
・starling・phoenicurus・turtledove・rock doveW・carrion crowA・little egret
・helonT・halcyonE・white-eyeRS

Birds(aquatic)
・spot-billed dock・dabchick・mandarin duck・tufted duck・teal
Reptile・mallard
・red eared slider
・cormorant ・soft-shelled turtｌe

coal ashsandenlargedfish
・mosquitofish
・carp
・northern snakehead・mullet・eel

Sludge accumulate on the smallest depression.

Sand particles near the bank.
Higher than other area.

26

Between Naka Bridge(in front) and Gojo Bridge

Between Gojo Bridge(in front)and Naka Bridge

sand
sand
coal ashcoal ashcoal ashJuly 31, 2015

sand
coal ashcoal ashJuly 31, 2015

sand

coal ashcoal ash

Aug 3, 2015

Aug 3, 2015

coal ash27

Downstream from Gojo Bridge(left bank)Downstream from Gojo Bridge (right bank)coal ashsand

July 31, 2015

sand

July 31, 2015

coal ash

Aug 3, 2015

Aug 3, 201528

5.15. Progress of Citizen s Awareness Activities of studies

堀川１０００人調査隊2010
第１８回調査隊会議
平成２８年２月６日（土) 報告：事務局

毎日新聞 ２月７日（日）朝刊

中日新聞 ２月２０日（土）朝刊

読売新聞 ２月７日（日）朝刊

123

Progress of Citizen s Awareness
Activities of studies
主催・協力・報告：黒川ドリーム会・御用水跡街園愛護会調査隊・ロマン黒川『伊勢湾流域圏再生フォーラム
連携と交流の輪を次世代に』
平成２８年３月５日（土）会場：名古屋文化短期大学

第６回堀川ラウンドテーブル 開催
キャッチコピー「いつも心に川がある」
堀川まちづくりの会
平成２８年３月１８日（金） 報告：事務局

飯田小学校３年生 堀川自然体験学習
平成２８年６月２日（木）名北小学校３年生 堀川自然体験学習
平成２８年６月６日（月）正木小学校５年生 堀川体験学習
平成２８年６月７日（火）大杉小学校３年生 黒川自然体験学習
平成２８年６月１０日（金）笹島小学校 黒川自然体験学習
平成２８年７月１４日（木）春の環境デーなごや２０１６
平成２８年６月４日（土）堀川体験乗船「身近な自然体験会〜
船から発見！私たちの堀川」主催：名古屋市環境局
運営協力：名古屋堀川ライオンズクラブ
場所：熱田区白鳥桟橋
飯田小学校３年生６０余名のお礼状
平成２８年７月２３日（土）報告：御用水跡街園愛護会調査隊

124Progress of Citizen s Awareness
Activities of studies
中日新聞 平成２８年7月26日（火）

堀川の再生と魅力を発信することを目的に
名古屋市議会の議員有志による「甦れ堀川名古屋市会議員連盟」が設立
中日新聞 平成２８年６月２９日（水）朝刊

下水道展が名古屋で開催
平成28年7月26日〜7月29日
堀川１０００人調査隊が参加
場所：ポートメッセなごや 報告：事務局

水環境ひろば 7月28日

メキシコ市上下水道局の職員の方々を堀川の体験乗船にご案内
名古屋・堀川での市民活動や行政との連携活動をご紹介
平成２８年７月２０日（水） 午後
場所：納屋橋〜名古屋港 案内・報告：事務局

125

Horikawa Clean Experiment with Chinese Water Spinach and SunPatiens
By Ena Agricultural High School, Nagoya Horikawa Lions Club
June 17th 〜 October, 2016
and EspecMic Corporation
Place：near the pier of Naya Bridge

experiment started June 17th

July 15th

June 24th

July 22th

July 1st

July 27th

July 8th

Aug. 5th126

Activities of “Free Survey Groups” & “Cheering Groups”
堀川上流部 桜の木の剪定
平成２８年１月２７日（水）報告：御用水跡街園愛護会調査隊

瑠璃光橋の下流に瀬淵の新設工事
平成２８年１月２７日（水）報告：御用水跡街園愛護会調査隊
中土戸橋地下水通水式 平成２８年３月２３日（水）報告：御用水跡街園愛護会調査隊
堀川ギャラリー展示会「私たちは堀川を見守っています」〜憩いの場になることを願って〜
名古屋市高年大学環境学科２９期調査隊
平成２８年２月２３日（火）〜３月１３日(日）

御用水跡街園 柵の補修とライトアップ
平成２８年３月２６日（土）報告：御用水跡街園愛護会調査隊

園児のお花見平成２８年３月２９日（火）報告：御用水跡街園愛護会調査隊

堀川の地下水放流地点へ
北ホームニュースを案内
瀬古橋〜辻栄橋〜木津根橋〜稚児宮橋〜志賀橋〜北清水橋〜中土戸橋
平成２８年４月４日（月）報告：御用水跡街園愛護会調査隊

127Activities of “Free Survey Groups” & “Cheering Groups”

三階橋郵便局でミニ写真展
平成２８年４月１４日（木）報告：御用水跡街園愛護会調査隊

第７回 春の堀川一斉大そうじ
主催：クリーン堀川
平成２８年４月１６日（土）報告：事務局

堀川ギャラリー 油絵展
平成２８年５月３１日（火）報告：御用水跡街園
愛護会調査隊
堀川１０００人調査隊が国土交通大臣から表彰されました
平成２８年８月１日（月）場所：科学技術館サイエンスホール （東京）

清掃活動
御用水跡街園
愛護会調査隊
場所：御用水跡
街園周辺
清掃活動
愛知銀行
場所：御用水跡街園周辺

堀川の川開きを開催
黒川ドリ−ム会と堀川まちネットのみなさん
平成２８年５月２９日（日）報告：御用水跡街園愛護会調査隊

清掃活動
ぎふしんムーミン清水支部 堀川応援隊
場所：北清水橋周辺

清掃活動
中日本建設コンサルタント㈱かわせみ調査隊
場所：錦橋〜納屋橋間

128

Progress of Citizen s Awareness
Activities of “Free Survey Groups” & “Cheering Groups”

水質調査活動報告 明電舎錦調査隊
平成２７年８月〜平成２７年１２月まで

鯱城・堀川と生活を考える会等が主催した「第４回 鯱城・堀川清掃大作戦」の報告書定点観測の活動報告
鯱城・堀川と生活を考える会
実施日 平成２７年１１月７日（土）http://www.horikawa1000nin.jp/katudou/2015-05-11-meidensha.htm

鯱城・堀川と生活を考える会
平成２７年度 堀川浄化活動報告書

新堀川水質調査報告
チームＮＴＴスマイルなごや
平成２７年１０月〜平成２８年４月分

活動報告 「上流は下流を思い、下流は上流に感謝する」
水源の里を守ろう 木曽川流域みん・みんの会

活動レポート：
環境ボランティアサークル「亀の子隊」

活動レポート：
伊勢湾流域圏再生ネットワーク事務局

129Progress of Citizen s Awareness
Activities of “Free Survey Groups” & “Cheering Groups”

日本下水道新聞に連載
市民とともに
母なる堀川の浄化〜下水道展 １６
名古屋に向けて〜
平成28年1月20日〜7月20日全27回連載閲覧用ＨＰ
http://www.horikawa
1000nin.jp/katudou/2016-01-06nihongesuidousinbun.
htm

130

Progress of Citizen s Awareness
Events

下呂市馬瀬地域の皆さんが来名鯱城堀川と生活を考える会の皆さんと上下流交流会を開催
平成２８年１月２０日（水）場所：堀川ギャラリーほか
報告：事務局
ナヤマルシェ開催と災害義援金募集
平成２８年４月２３日（水）撮影：御用水跡街園愛護会調査隊

堀川友禅流し 平成２８年４月２日（土）主催：北区民まちづくり推進協議会
報告：御用水跡街園愛護会調査隊
堀川フラワーフェスティバル２０１６開幕
平成２８年５月１３日（金）〜２８日（土）報告：御用水跡街園愛護会調査隊、事務局

131

Progress of Citizen s Awareness
Events

第１２回「堀川エコロボットコンテスト２０１６」説明会
平成２８年５月２１日（土）主催：名古屋堀川ライオンズクラブ
協賛：名古屋工業大学
なごや水フェスタ開催（鍋屋上野浄水場解放イベント）
平成２８年６月５日（日）場所：鍋屋上野浄水場 (名古屋市千種区）
主催：名古屋市上下水道局参加した調査隊：名古屋市高年大学環境学科３０期調査隊
名古屋堀川ライオンズクラブ調査隊
報告：事務局

堀川まつり
平成２８年６月４日（土）報告：御用水跡街園
愛護会調査隊

報告：御用水跡街園愛護会調査隊「いい木曽見つかるキャンペーン」
平成２８年７月１日〜１１月７日

132