Horikawa Sen-nin Chosatai 2010
(Horikawa River Thousand Citizen Survey Network 2010)

Summary Meeting for the 11th Stage(September 22nd 2012)
Horikawa Sen-nin Chosatai 2010 secretariat

1Horikawa River Pilot Project-Transmission of Raw Water from the Kiso River (TRWKR) –Surveys during TRWKR period : April 2007 ～ March 2010
Surveys after the stop of TRWKR : April 2010～ March 2012 The formation of Horikawa Sen-nin Chosatai (HSC)(April 22nd 2007)
1) Fixed Point Observation Groups
2) Free Survey Groups
The survey with a view point and a3) Horikawa Cheering Groups
sense of citizens

To verify the 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 make a wish for clarification and restoration of the
Horikawa River was grown.
■ Citizens’ awareness of cleaning of the river was developed

3

Horikawa River Pilot Project-Transmission of Raw Water from the Kiso River (TRWKR) –Surveys during TRWKR period : April 2007 ～ March 2010
Surveys after the stop of TRWKR : April 2010～ March 2012

■ 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 will make a improvement plan and take action to the pollution.
•After that, citizens and public administration will do what is possible toclean the river.
(2) There are many things that citizens can.
・We will expand the circle of partners who love the Horikawa River andhope the TRWKR.
・We will deepen exchanges with people living in the basin of the Kiso,
Nagara, and Ibi River.
・We will check the effect of pollution removal from domestic wastewaterand implement it in each house.

3

Number of Participnants of Horikawa
Sen-nin Chosatai 2010
Horikawa Sen-nin Chosatai started accepting participation
on March 26th ,2007

Start
Apr.22th 2007
Fixed Point
Observation Groups

55 groups
497 persons

Free Survey Groups

22 groups
234 persons

Horikawa CheeringGroups

88 groups
1,531 persons

Total

165 groups
2,262 persons

Now
Feb.20th 2012
91 groups
906 persons
40 groups
650 persons
2,457 groups
44,029 persons
2,588 groups
45,585 persons

5Survey period and Number of reports
Survey Period(With TRWKR)

Number ofReports

1st stage

Spring ～ early summer / Apr.22nd ～Jun.30th 2007

258

Interval

Jul.1st ～Sep.7th 2007134

2nd stage
Interval
3rd stage
Interval
4th stage
Interval
5th stage

Autumn ～ early winter / Sep.8th ～Dec.16th 2007
Dec.17th 2007～Mar.31st 2008
Spring ～ early summer / Apr.1st ～Jun.30th 2008
Jul.1st ～Sep.27th 2008
Autumn ～ early winter / Sep.28th ～Dec.16th 2008
Dec.17th 2008～Mar.31st 2009
Spring ～ early summer / Apr.1st ～Jun.30th 2009

383
103
245
64
152
100
145

Interval

Jul.1st ～Sep.26th 200954

6th stage

Autumn ～ early winter / Sep.27th ～Dec.16th 2009

120

Interval

Dec.17th 2009 ～ Mar.31st 201081

7

Survey period and Number of reports
Survey Period(Without TRWKR)

Number ofReports

7th stage

spring～early summer / Apr.1st ～Jun.30th 2010

111

Interval

Jul.1st ～ Sep.11th 201044

8th stage
Interval
9th stage
Interval
10th stage
Interval
11th stage

Autumn～early winter / Sep.12th ～Dec.17th 2010
Dec.17th 2010～Mar.31st 2011spring～early summer / Apr.1st ～Jun.30th 2011
Jul.1st ～Sep.10th 2011
Autumn～early winter / Sep.11th～Dec.16th 2011
Dec.17th 2011～Mar.31st 2012spring～early summer / Apr.1st ～Jun.30th 2012

104
72
112
42
133
77
148

Total

2,682

7

The main measures of the pilot projectMeasures

2007

2008

2009

2010

2011

2012

1st.

3st.

5st.

7st.

9st.

11st.

2st.

4st.

6st.

8st.

10st.

TRWKR(0.4m3/s)
Increase of raw water transmission
from the Shonai River (+0.4m3/s)

The main measures implemented by
City of Nagoya
Measures

2007

2008

2009

2010

2011

2012

1st.

3st.

5st.

7st.

9st.

11st.

2st.
Advanced water treatment at the
Meijo water treatment center
The Horikawa Ugan Rain-water
Reservoir for pollution controll
Reclaimed wastewater from theMoriyama water treatment
center(0.046m3/s)

4st.

6st.

8st.

10st.

The facilities after the stop of TRWKR
 Improvement of the quality of treated water
The additional filtration of treated water at the Meijo
Water Treatment Center leads to the improvementof quality of the water sluiced into Horikawa River.
Meijo Water Treatment Center (Advanced water treatment)
Solution: conventional activated sludge process ＋ rapid filtration
Launch (rapid filtration): May. 2010

 Improvement of combined sewer system
By capturing and storing first flush with high-pollution
load temporarily, the frequency of overflow from thesewer outlet can be reduced.
Horikawa Ugan Rain-water Reservoir for pollution control
Volume: 13,000m3
Coverage Area: 633ha
Launch: Sep. 2010

通水開始 平成23年8月

資料：第１０回 堀川１０００人調査隊会議

14

１・３・５ Stage ： TRWKR
Impression of clearness・・・Spring～Early Summer The
No rain on the day and the previous day

Proportion between “Clear” and “Neither”

The ７・９・11 Stage： No TRWKRNo rain on the day and the previous day

Except the section with a small data Minatoshin Bridge ～ Oseko Bridge ,Sanage Bridge ～Sakae Bridge

100

Oseko Bridge～Matsushige Bridge

Matsushige Bridge～Asahi Bridge

Asahi Bridge～Johoku Bridge

Johoku Bridge～Sanage Bridge

TRWKR
Introduction of advanced water treatment introduction at Meijo Water Treatment Center

impression of clearness（％）

Launch of Horikawa Ugan Rain-water Reservior for pollution controll
Use of reclaimed wastewater at Moriyama Water Treatment Center

80

Improved
During TRWKR period
Between Sanage Bridge and Matusige Bridge

60

53

43
40

Tendency of improvement by the practiceof the new policy in the water quality improvement

Deteriorated
After the stop of TRWKR

36

40

29

27
23
20

18

16
11

21

28

23

22

21

23

16

12

12

8

6

5
0

0

0

2007.4.22～6.30

2008.4.1～6.30

2009.4.1～6.30

2010.4.1～6.30

2011.4.1～6.30

2012.4.1～6.30

1st stage

3rd stage

5th stage

7th stage

9th stage

11th stage■ After the stop of TRWKR, how did the impression of clearness change (spring～early summer）？
→In 7th stage after the stop of TRWKR, impression(“clean” or “not applicable either”) was deteriorated. But
afterward we have seen is the tendency of improvement. This is considered to be an effect of the new water
quality improvement measures.

16

3rd・5th stage ： TRWKRNo rain on the day and the previous day
7th・9th・11th stage： ： No TRWKRNo rain on the day and the previous day

Rain or no rain on the previous day・・・ Spring～Early Summer

Impression of clearness Sanage Bridge～ Minatoshin Bridge
The 3・5・7・9・11stageTRWKR and No TRWKR No rain on the day and rain on the previous day

Minatoshin Bridge Oseko Bridge

Matsusige Bridge

Asahi Bridge

Oseko Bridge ～Matsushige Bridge
4%1%⑦others⑦その他

90%⑥living⑥生き物の様things子⑤bubble
⑤あわ

80%

80%

70%

70%

90%

13%

15%

1%

100%

1%

②smell②においRatioofofimpression(％)
Impression(%)
Ratio③
transparency
③透明感

100%

5%
2%

90%

90%

17%

30%

④garbage④ごみ

Asahi Bridge ～Johoku Bridge

Matsushige Bridge ～Asahi Bridge

3%

100%

Johoku Bridge ～Sanage Bridge
100%

2%
14%

90%

17%

80%

80%
10%

60%

TRWKR

B． No rain on the day and Rain on the previous day

Minatoshin Bridge ～Oseko Bridge
100%

Sanage Bridge

Meijo water treatment center

Shin-Horikawa River confluence
A． No rain on the day and the previous day

Johoku Bridge

8%

60%

up

up

70%

16%

80%

14%

6%

70%
60%

60%

70%

67%
3%

60%

34%

40%

100%

50%
21%

40%

40%

30%

30%

63%

50%

50%

50%

40%

40%

40%

4%

30%

30%

60%

30%

60%

50%

20%

①water
color
①色

20%

30%

10%

0%
①
A

10

20%

20%

10%

10%

20%

②
B

1

0%

0%

42%

4%

33%

33%

10%

up
68%

12%

50%

8%

21%

15%

29%

3% 1%

20%

10%
0%

0%

①

A

②

B

A①

B②

A

B

142

24

218

42

58

3

①

②

Small data

①
A

②
B

146

25

Small data

②and③ is increased when it rains② is increased when it rains③ is increased when it rains■ After the rain on the previous day, how did the change impression of clearness (spring～early summer）？
→ ② is increased between Sanage Bridge and Johoku Bridge. ② is increased between Asahi Bridge and Matsusige Bridge. The
evaluation of clean and smell is increased between Matsusige Bridge and Oseko Bridge.

18

The １・３・５ Stage ： TRWKRNo rain on the day and the previous day
The ７・９・11 Stage： No TRWKRNo rain on the day and the previous day

The change of transparency・・・ Spring～Early Summer
Except the section with a small data Minatoshin Bridge ～ Oseko Bridge ,Sanage Bridge ～Sakae Bridge

Oseko Bridge～Matsushige Bridge
Asahi Bridge～Johoku Bridge

Matsushige Bridge～Asahi Bridge
Johoku Bridge～Sanage Bridge

TRWKR

100

Advanced water treatment introduction
at Meijo water treatment center

Horikawa Ugan Rain-water Reservior for pollution controll
Application of reclaimed wastewater at Moriyama water treatment

transparency(cm)80

Improved
During TRWKR period
Between Sanage Bridge and Matusige Bridge
71

Tendency of improvement by the practice
Deterioratedof the new policy in the water quality improvement
After 68
the stop of TRWKR
65

60

59

59 58
53

61

60 61

56
52

58

56

54

52

64

63

60

57
51

54
48

43
40

20

0

2006.4.22～'07.12.16

2007.9.8～12.16

2008.9.28～12.16

2009.9.27～12.16

2010.9.11～12.17

2011.9.11～12.16

1st stage

3rd stage

5th stage

7th stage

9th stage

11th stage■ After the stop of TRWKR How did the change impression of clearness (spring～early summer）？
→In 7th stage after the stop of TRWKR, transparency was deteriorated. But afterward we have seen thetransparency of improvement. This is considered to be an effect of the new water quality improvement measures.

21

The average of transparency if it rained on the previous day
Sanage Bridge ～ Minatoshin Bridge
・1st・3rd・5th・7th・9th・11th stage including all data ( TRWKR and No TRWKR ) ・No rain on the day

Transparency became low after it rained
Not enough data

2

157

29

203

45

61

5

Injection Point of TRWKR

Shinhorikawa River

Nagoya Port
Number of data 14

MeijoWaterTreatment Center

Citizen feels OK above 70cm

145

30

Note） The value of 100cm or more was treated as 100cm■ How did transparency (spring～early summer)change if it rained on the previous day ?
→Transparency became low after it rained.
Especially, the transparency became lower between Asahi Bridge and Minatoshin Bridge .

22

Change in COD・・・spring～early summer

1st・3rd・5th stage ： TRWKRNo rain on the day and the previous day
7th・9th・11th stage： No TRWKRNo rain on the day and the previous dayNote） Rule out the data of “Minatoshin Bridge ～Oseko Bridge” and the data of “Sanage Bridge ～Sakae Bridge” for not enough data.

TRWKR

Introduction of advanced water treatment introduction at Meijo Water Treatment Center
COD was improved between Sanage Bridge
and Matsushige Bridge during TRWKR

Launch of Horikawa Ugan Rain-water Reservior for pollution controll
Use of reclaimed wastewater at Moriyama Water Treatment Center

There was no marked change after the stop of TRWKR■ How did COD (spring～early summer)change after the stop of TRWKR ?
→There was no marked change in COD after the stop of TRWKR

25

The average of COD after rain on the previous day
・・・spring～early summer Sanage Bridge～Minatoshin Bridge
・1st・3rd・5th・7th・9th・11th stage including all data ( TRWKR and No TRWKR ) ・No rain on the day

Nagoya Port

Shinhorikawa River

Not enough data

Number of data

14

2

159

29

215

49

72

6

■ How did COD (spring～early summer)change when it rained on the previous day？
→The notable change of COD was not found by rain.

Injection Point of TRWKR

MeijoWaterTreatment Center

The notable change of COD was not found by rain.

190

36

26

・1st-6th stage ： TRWKRNo rain on the day and the previous day
・7th-11th stage ： No TRWKRNo rain on the day and the previous day

The occurrence of bubbles
Not enough data

Period of TRWKR① Introduction of advanced water treatment
at the Meijo water treatment center.

Number of data

② Launch of the Horikawa Ugan Rain-water
Reservoir for pollution control.

①

Period of TRWKR

②
③

ⅰ
ⅱ

ⅲ

③ Use of reclaimed waste waterat the Moriyama water treatment center.
ⅰ)Decreasing the frequency ofthe occurrence of bubbles.
ⅱ)Increased after the stop of TRWKR.
ⅲ)The bubbles tended to decrease forthe new implemented
water quality improvement measure .

Number of data

■ How did the bubbles change ?
→The frequency of occurrence of bubbles “spring～early summer” was higher than “autumn～early winter”.
And the frequency of occurrence of bubbles decreased during TRWKR.
The bubbles increased after the stop of TRWKR(7th stage). But after that, the bubbles tended to decrease.
This is considered to be an effect by the new implemented water quality improvement measure.

28

５． Smell

1st ～ 6th stage ：TRWKRNo rain in the day and the previous day
7th ～ 11th stage：No TRWKRNo rain in the day and the previous day

Sakae bridge ～ Sanage bridge
During TRWKR period（Reference)Offensive Odor Control Law
Regulatory standards at the boundary of factories orworkplaces is defined as the density of specific malodorous
substance corresponding to the intensity of 2.5～3.5 in“Indicator Method of 6-Level-Odor-Intensity”.
intensity

A few data(not enough data)

Numberof data 23

40

15

2

8

3

5

8

5

9

9

Sanage bridge ～ Minatoshin bridge

smell degree0

no smell

1smelly enough to sense2

smelly enough to find out what kind of smell

3

smell easily to realize

4

bad smell

5

Extremely strong smell■ How did the smell change?
There were more “Bad smell” and “Rather bad
smell” in spring-early summer season thanautum-early winter season.

During TRWKR period
Introduce the advanced water treatment in Mejo WWTC
Running the combined sewer reservior
Reclaimed wastewater in Moriyama WWTC

“Bad smell” and “Rather bad smell” decreasedin the during TRWKR period.
“Bad smell” and “Rather bad smell” decreased
after the stop of TRWKR (7th stage). But after
that, smell decreased (became better). This isconsidered to be the effect of the newly
implemented water-quality-improvement
measures.

Numberof data

108

212

176

52

111

63

84

67

75

113

110

31

The component ratio of the Color

1st～6th stage ：TRWKRNo rain in the day and the previous day
7th～11th stage：No TRWKRNo rain in the day and the previous day

between Sanage bridge and Minatoshin bridge

The “color” was added to the survey list from the 2nd stage.

High Frequency: ⑧light gray yellow green, ⑨gray yellow green, ⑩gray green① colorless⑥ gray⑪ dark gray② milk white⑦ yellow gray⑫ light yellow
gray③ yellow⑧ light grayyellow green⑬ yellow brown④ yellow green⑨ gray yellow
green⑭ brown⑤ green⑩ gray green⑮ green brown■Which color was seen frequently?
→⑧light gray yellow green, ⑨gray yellow green, and ⑩gray green appeared frequently. The ratio of ⑮green brownslightly increased in the 11th stage. It was considered because there were many phytoplanktons in the river.

36

７． Garbage

From 2nd to 6th stage : TRWKRNo rain on the day and the previous day
From 7th to 11th stage：No TRWKRNo rain on the day and the previous day

Garbage on the road
Change of frequency that artificial garbage were found■What is artificial garbage？：
Plastics(shopping bag, vinyl bag, noodle cup, polystyrene foamed tray,
PET bottle, shopping bag with garbage, etc.), can, bottle, cigarette(wrapping, tray)■How has the frequency of finding garbage on the road changed？
Garbage has been in decreasing trend. Growing of cleaning activities and charge for the plastic shoppingbags etc. may be causes of this trend. The most frequent item to be found is “cigarette butt”.

cigarette butt

cigarette wrapping

other papers

magazine

newspaper

paper bag

paper carton

glass bottle

canplastic bag withgarbagecity-specified plastic
bag with garbage

pet bottles

other plastics

polystyrene foam tray

noodle cup

other vinyl

plastic bags

Total of18 itemsof garbage
in eachstage.

plastic shopping bags

28
26.0
26
「Plastic shopping bag1.8」 means that
2nd stage・All sections
3rd stage・All sections
24
Plastic shopping bag was found 1.8 times
4thstage・All
sections
5th stage・All sectionsin 10 investigations (or 18 times in 100
22
6thstage・All
sections
7th stage・All sections
investigations).
8th stage・All sections
9th stage・All sections
20
10th stage・All sections
11th stage・All sections
18
16
Frequency of finding garbage(/10 surveys)
14
12.4＝number of surveys in which garbage was found/number of surveys ×10
12＊Frequency of finding garbage is not same as the number of garbage. If
garbage is found one or more times in each survey, it counts just one.
10
8
Garbage: in decreasing trend6
3.6 3.8
1.5
2.4
4
2.5
2.2
1.8
2.0
1.8
0.4
1.5
1.0
1.8
1.1
0.5
1.0
0.5
0.4
1.0
0.9
0.7
0.7
0.7
0.7
2
0.6
0.5
0.5
1.2
0.4
0.2
0.1
0.1
0.0
0.4
0.1 0.00
Total

frecuency (/10 survesys )（2nd-11th stage, All sections））

39

From 1st to 6th stage : TRWKRNo rain on the day and the previous day

the number of garbage per one survey

Floating substance
Change in floating garbage■What is artificial garbage？：
Plastics(shopping bag, vinyl bag, noodle cup, polystyrene foamed tray,
PET bottle, shopping bag with garbage, etc.), can, bottle, cigarette(wrapping, tray)

All sections

The sum of each stage,
the number of garbage
per one survey

5
4

3.4
3.0

Many plastics garbage found3

From 7th to 11th stage：No TRWKRNo rain on the day and the previous day

1st stage
3rd stage
5th stage
7th stage
9th stage
11th stage

Cleanup
Vessel

2nd stage
4th stage
6th stage
8th stage
10th stage

2.3

2.2

2

Floating garbage not in decreasing trend

1
0.4

0.5

0.3
0.1

0.3

Total

Plastics

Cans

0

0

0
Bottles

0.3

PapersCigarettes

Note: the number of garbage per one survey= the number of each artificial garbage found in all surveys /the number of surveys＊the number of garbage is the number of garbage found through all surveys“if some kind of garbage was found “many(= ***)” in some survey, it counts “10”, the maximum number in one survey
substituted for the number of “many”.

■How has the floating garbage (artificial garbage) changed？
→Floating garbage have not decreased although garbage on the road is in decreasing trend.
Floating garbage is periodically removed by the cleanup vessels, but garbage thrown into
Horikawa is moved between estuary basin zone by the tidal effect, so they are stagnant for along time. Many of floating garbage found are “Plastics”.

Survey numbers
1st Stage：145
2nd Stage：255
3rd Stage：191
4th Stage： 54
5th Stage：119
6th Stage： 66
7th Stage： 90
8th Stage： 75
9th Stage： 81
10th Stage：122
11th Stage: 122

41

Report about floating garbage in Horikawa River
JOURNAL OF HYDROSCIENCE AND HYDRAULIC ENGINEERING, No.52, Feb, 2008
Study on the Transport Characteristics of Floating Garbage inHorikawa River
Makoto TAKEDA, Morihiro HARADA, Akihiro TOMINAGA, Shozou
ISHIGURO, Takayuki KONDO, Yoshiro NAKASHIMA, and Hitoshi
YOSHIDA（Summary）
1) More than 70 % of floating garbage is natural one. A lot of
artificial garbage appears in downstream area. The mostappearing natural garbage are dead trees and grasses entering
into Horikawa River.
2) Floating garbage in downstream area near Hioki Bridge flows on
the side, especially on the right bank, at the ebb, while they flows
upstream on the center and both sides at the rising tide.
3) The water area in Matsushige lock makes effect on transport of
garbage near Hioki Bridge. When it is ebb tide, floating garbage
flows into the right bank of water area of Matsushige lock andgathers, then when it turns high tide, garbage flows out to wholesurface.
4) By monitoring the garbage with GPS system, it was confirmed thatthe floating garbage transports between the middle basin section
and Matsushige lock area again and again.
5) It was made clear that the water area of Matsushige lockcontributes the prolongation of garbage floating, therefore the
Horikawa River has the river with floating garbage.
6) By numerical analysis, it was shown that the transport of floating
garbage in water area of Matsushige lock was caused mainly bydensity change of tidal phenomena in Horikawa River.
7) Based on the knowledge obtained, effective measures for
garbage can be expected.

42８． Living things
Ａ area：Chigomiya Bridge

The 2nd survey reault of living things (Horikawa bioliversity meeting)Date ：May 20thGrouping

Speciesname
A areaReptilian

red eared slider

FigureB areaturtletRecitalC areavisual contact(male-3,female-4)

Fishfloating goby
gnathopogon elongatus
carp

1
1
visual contact(many)

hemibarbus barbus
nile tilapia

Ｂ area：Downstream of Sanage Bridge
Crastacea

Insect kind
Shelifish
Waterweedneocaridina denticulata
japanesemitten crab
corixidae
odonate lara of dragonify
thiaridal snail
corbicula leana
potamogeton oxyphyllus
eelgrass
egeria densa

alevin(many)
visual contact(many)
carp(2)
1

visual contact(2)

including carp

1
10
2
1
some
some
some
many
many
a little

many

Ｃ area：Nakatsuchido Bridge

The 3rd surbey result of living things (Horikawa bioliversity meeting)Date：June 22nd
Confirm of 12 kinds of living things in upper stream Horikawa
Photo：secretariat

47

Experiment of Horikawa clarification by water spinach
Collaborative experiment with Ena agricultual high schooland Horikawa Lions club, this year again
Area ： Around of Naya Bridge

June 22nd～

Eyewitness report of
the alien organism

Nile tilapia
Upstream of Nakatsuchido
BrigdeReport : secretariat

Myocastor coypus
The first week

2012.6.16
Around Kurokawa No1Bridge.
Some eyewitness reports
around Shinhori Bridge.
2012.6.23
Around Tabata Bridge.

The third week

Report：Goyousui-ato-gaien-aigokai
Survey Group

Kind of Green crab
2012.7.2
Around Kameya Bridge
Report：Kawasemi survey group2012.7.5 Yaguma elementary school
5 grade as River Planning Division
Horikawa survey group observed a water
spinach at Nayai Bridge

The fifth week

Black bass
2012.7.2
Upstream of Nakatsuchido
BridgeReport : secretariat

Kind of Gar
2012.7.27 Nishiki
BridgeReport：Kawasemi survey group

The seventh week

The eleventh week

The ninth week49

９． About wind

Direction of wind
There are many direction of winds
along Horikawa riverWind for upstream
100

80

80

80

60

60

60

40

40

0

7%

From side53%

8%

Wind for side

Koshio Bridge11%
For upsteam

0

51%

80

80

60

60

40

40

None
wind

37%
１～１１ stage
Number of survey 63

33%

From side

20

None
wind

0

29%

32%

１～１１ stage
Number of survey 12213%yFor downstream
Oto Bridge
For upsteam

Nishiki Bridge
For upsteam 33%
100

For downstream

From side

１～１１ stage
Number of survey
53

100

19%

None
wind

For downstream 11%

For downstream20%

20
0

100

40

20

None
wind
1st～11th stage
Number of survey 45

From side

30%

100

20

From side

Johoku Bridge
For upsteam 26%

Kitashimizu Bridge
For upsteam

Meoto Bridge
For upsteam 20%

100

9%

80
60
40

20
0

11%

20

None
wind

From side

11%

4%

29%
１～１１ stage
1 of survey 107
Number１～１１ stage
Number of survey 189
For downstream 45%

None
wind

0

For downstream

58%

Wind for downstream■How about the direction of wind？
We are organized it used all dates on
the 11th stage from first stage.
It seem that there are more winds
along Horikawa river than crossing it.
About 80% of wind blows along
Horikawa river around Nishiki Bridge.

5010. The Conclusion of the 1st Horikawa general investigation
appearance of Horikawa at the time of spring tide
Horikawa Sen-nin Chosatai

The 1st Horikawa general investigation
Investigation day: May 20th,21st in 2012
In nagoya, it was annular solar eclipse for the first time in 932 years.
(the morning on May 21st)
The sun, the moon and the earth are located in a straight line.

Photo taken by Kojo-Horikawa-to-seikatsu-wo-kangaeru chosatai■The main points
paying our attention

This day is spring tide- The period when
the water level is lowest in every year
The water level of Horikawa(between Sanage Bridge and Mouth) is subject tothe influence of the sun and the moon.

Reference: National Astronomical Observatory of Japan Public Relations Center① Change of color,
smell,bubble

If the time of investigation changes, the state of color of water,smell and bubble may change.

② The state of riverbottomWe may be able to see the state that tide roll up sludge.

③ Appearance ofliving thing④ Appearance of tide

Please observe the water surface and a water's edge.
If dissolved oxygen is not enough, the kind of fish, crab, or shrimp
will take refuge in the place near the water surface.
We may be able to the state of high and ebb tide.

51

The tide level of Nagoya Port in May 2012
Spring tide_annular solar eclipse
Neap tide
May 21st
Ebb tide：12:10
High tide：19:39

The 1st Horikawa generalinvestigation on May 20th, 21st

Spring tide

Neap tide

Difference ofthe tide level
104cm

Difference ofthe tide level
207cm

・The difference oftide level of Nagoya
Port of the day ofspring tide(annularsolar eclipse) was
more than 2m.
・The difference oftide level of springtide was twice ofneap tide.

52
Reference: Japan Meteorological Agency

As the tide level changed, the direction ofHorikawa's stream changed.

① Change of the direction of the stream

The tide levelof Nagoya PortMay 21st
Ebb tide：12:10
High tide：19:39

The tide level (T.P.cm)

150

Ebb tide100

High tide

50
0
6

7

8

9

10

11

12

15

16

17

18

19

Reference: Japan Meteorological Agency-150

Observation point

7:00

8:00

9:00

↓

↓

↓

Johoku Bridge
Nakatsuchido Bridge↓

Sujichigai Bridge

↓
↓

↓
↓
↓

Tennouzaki Bridge

Matsushige Bridge

Oto Bridge

↓
↓

↑
↑

↓

Habashita Bridge

Nishiki Bridge
Naya Bridge↓

Ebb tide

↑
↓

↑

↑

↓

↓
↓

Sumiyoshi Bridge

↑
↑

↑
↑

The stream tothe upper wasobserved at
Johoku Bridge.

↓↑↑

Atsutakinen Bridge

Oseko Bridge

The stream to the upper

10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00↓↓

Sanage Bridge
Kitashimizu Bridge

time

↓

Meoto Bridge
Siga Bridge

・As the tide level of
Nagoya Port changed,
the direction ofHorikawa’s streamchanged.
・The stream to theupper was observed
at Johoku Bridge.

14

-100

The stream to the lower

The direction ofHorikawa’s stream

13

-50

↓

Kizaemon Bridge* An arrow shows direction of the stream of the observation time.

↓

↑
－

↑

↑
↑
↑

High tide↑↑54

② Change in the impression of cleanness
1：clean

2：slightly clean

3：fair・ The impression of cleanness gets worse around the timeslot of low tide.
・ After switching to flood tide, the impression of cleanness
gets worse from a point of downstream.

4：slightly dirty

5：dirtypoint name 7 a.m. 8 a.m. 9 a.m. 10 a.m. 11 a.m. 12 a.m. 1 p.m. 2 p.m. 3 p.m. 4 p.m. 5 p.m. 6 p.m. 7 p.m.
・During the time slot
Meoto Bridge
2↓
A comment of “Kojo・Horikawa”
between falling tide andSanage Bridge
1↓■Habasita bridge at 12 oclock ・・・ While
low tide, there are many
Shiga Bridge
4↓ 2↓both banks are dirty with mad, rocks on the
points of “slightly dirty～
Kitashimizu Bridge 5↓ 2↓ 4↓ 4↓ 4↓ 2↓
bottom of the river are clean.
dirty”. Especially, The
Johoku Bridge
5↓4↓2↑
impression of cleanness
Nakatsuchito Bridge
4↓ 4↓
gets worse around the
Suzikai Bridge
3↓
4↑
time slot of low tide.
Habashita Bridge
2↓
・As switching to flood
Nishiki Bridge
3↓
5↑
3↑
5↑
tide, some points
Naya Bridge
4↓2↑ 3↑ 4↑
improved temporarily,
Tennozaki Bridge
after then the points of3↓“slightly dirty～dirty”
Matsushige Bridge
3↑
increased.
Oto Bridge
5↓5↓Sumiyoshi Bridge
4↓
2↑
4↑
Atsutakinen Bridge
3↑ 3↑
Oseko Bridge
5↓
4↓ 2↑
4↑ 3↑
4↑
Kizaemon Bridge
5- 4↑Note） The arrow on the right of the value shows the direction of flow at the time of observation

get worsetide level・
T.P.cm

150
100
50
0
-50 6
-100
-150

7

During the time slot between
falling tide and low tide, there
are many points of “slightly
dirty～dirty”

8

9

A comment of “Kojo・Horikawa”■Oseko Bridge ・・・ As overall impression, transparency
and color is worse.

10 11 12 13 14 15 16 17 18 19
time

Note T.P : mean sea level of Tokyo Bay

Reference: Japan Meteorological Agency

May 21th
Ebb tide: 12:10 p.m.
High tide: 19:39 p.m.

55

③ Change in color

Color of the water changed depending on the time slot of survey
May 21th
Ebb tide: 12:10 p.m.
High tide: 19:39 p.m.

point name

7 a.m. 8 a.m. 9 a.m. 10 a.m. 11 a.m. 12 a.m. 1 p.m. 2 p.m. 3 p.m. 4 p.m. 5 p.m. 6 p.m. 7 p.m.

1↓

Meoto Bridge
Sanage Bridge
Shiga Bridge
Kitashimizu Bridge
Johoku Bridge
Nakatsuchito Bridge

Suzikai Bridge

9↓

1↓
5↓ 1↓
9↓ 9↓ 9↓ 9↓
8↓
10↓ 10↓8↓

It’s thought to be due to9↓ roll up sludge.
8↓

8↑
10↑

8↓

Habashita Bridge
Nishiki Bridge

7↓

10↑
9↓

Naya Bridge

15↑10↑
8↑ 10↑ 9↑

Reference: Japan Meteorological Agency

8↓

Tennozaki Bridge

7↑

Matsushige Bridge
Oto Bridge

Tide level of
Nagoya port

Greenish gray

7↓

9↓
9↓

7↑
Atsutakinen Bridge
15↑ 10↑
Oseko Bridge
9↓
13↓ 9↑
13↑ 15↑
10↑
Kizaemon Bridge
15- 15↑Note） The arrow on the right of the value shows the direction of flow at the time of observation.
Sumiyoshi Bridge

8↑①Colorless⑥Gray⑪Dark gray②Milky white⑦Yellowish⑫Pale Yellowish

gray

gray

③Yellow⑧Pale yellow-⑬Tan

green ash
④Yellow-green⑨Yellow-

Green brown・Greenish gray was observed a
lot at midstream. It’s thought tobe due to roll up sludge.
・During a time slot of falling tide,
green-brown was observed a
lot at mid・downstream. It’sthought to be due to red tide(overgrowth of phytoplankton).

It’s thought to be due
to red tide.
During this time, red tide has
happened at Nagoya port.

⑭Browngreen ash
⑤Green⑩Greenish
gray⑮Green brown

Note T.P : mean sea level of Tokyo Bay

56

Mainly, “no smell～slightly smell”④ Change in smell
1：no smell

2：slightly smell 3：bad smell 4：sort of terrible smell 5：terrible smell

point name 7 a.m. 8 a.m. 9 a.m. 10 a.m. 11 a.m. 12 a.m. 1 p.m. 2 p.m. 3 p.m. 4 p.m. 5 p.m. 6 p.m. 7 p.m.
Meoto Bridge
2↓
A comment of “Kojo・Horikawa”
Sanage Bridge
1↓■Nakatsuchito bridge at 10 oclock ・・・ While color
Shiga Bridge2↓ 1↓of the water looked dirty, the water dipped up had no
Kitashimizu Bridge
1↓ 1↓ 1↓ 1↓
color and no smell.
Johoku Bridge
2↓
1↓
1↑
Nakatsuchito Bridge2↓ 1↓
While roll up sludge andSuzikai Bridge
1↓
1↑
red tide was observed,
Habashita Bridge2↓
excepting some results ofNishiki Bridge
1↓
2↑
1↑
3↑
survey, the result was
Naya Bridge
2↓
1↑ 1↑ 1↑
mainly “no smell～slightly
Tennozaki Bridge
1↓
smell”.
Matsushige Bridge
2↑
Thus the smell was slight.
Oto Bridge
1↓
1↓
Sumiyoshi Bridge
1↓
1↑
Atsutakinen Bridge
1↑ 1↑
Oseko Bridge
2↓
4↓ 2↑
2↑ 1↑
2↑
Kizaemon Bridge
1- 1↑Note） The arrow on the right of the value shows the direction of flow at the time of observationtide level・
T.P.cm

150
100
50
0
-50 6
-100
-150

May 21th
Ebb tide: 12:10 p.m.
High tide: 19:39 p.m.

7

8

9

10

11

Note T.P : mean sea level of Tokyo Bay

12

13
time

14

15

16

17

18

19

Reference: Japan Meteorological Agency

58

5 Change of smells

The reason of bad smell was Sludge

Smell of sludge

Meoto Bridge
Sanage Bridge

The reason is thought to be due tomixed sludge by flux and reflux of thetides

The reason of bad smell
was Sludge.
The Smell of sludge isthought to be due tomixed sludge by flux andreflux of the tides

Mar 21th
Ebb tide: 12:10
High tide:19:39

Note T．P : mean sea level of Tokyo Bay

It would appear that the smell of sea is due tocrop out algae on the sea wall by ebb water.

DATA of the japan Meteorological Agency

59

6 Change of bubbles

We observed bubbles from bottom of a river, when it was the term offalling tide at middle area, when it was the term of rising tide at lower area.

Meoto Bridge
Sanage Bridge

Drawdown → decrease in water pressure
Increase the water velocity → roll up sludge

Middle area

Gasses of methaneand others are given
off easily from sludge/At middle area, observed
bubbles from bottom of a riverwhen it was the term of fallingtide.
/At lower area, observed
bubbles from bottom of a riverwhen it was the term of risingtide.
/We consider that gases ofmethane and others are given
off easily from sludge. The
causes of these situation arethat drawdown lead todecrease in water pressure
and Increasing the watervelocity lead to roll up sludge

Lower area
Mar 21th
Ebb tide: 12:10
High tide:19:39

T.P 0m and under
Note T．P : mean sea level of Tokyo Bay

DATA of the japan Meteorological Agency

60

7 Change of Transparency

Mar 21th
Ebb tide: 12:10
High tide:19:39

Transparency becomes worse at ebb tide.
Transparency is temporarily-improved at the hightide, but it tends to become worse since then.

We suppose thattransparency become
worse by sludge frombottomdeterioration

Kojyou Horikawa to seikatuwo
kanngaerukai chousatai reports#Kitashimizu Bridge - Water quality
was bad by sludge at the term of
ebb tide

Mizumondai kennkyuujyo chousatai reports about
Jyouhoku Bridge at noon.
This area is shallow, so ebb tide may roll up the sludge

We suppose that transparency
becomes worse by red tide

deterioration#Oseko Bridge – The transparency become
worse with spring tide

Note T．P : mean sea level of Tokyo Bay
DATA of the Meteorological Agency

Transparency becomes worse at ebb tide. We suppose that the reason is raisedsludge from bottom.
Transparency becomes worse at high tide. We suppose that the reason is red tide;suspended substance as exemplified by phytoplankton.

61

・COD deteriorated during ebb tide・COD is temporarily-improved at the hightide, but it tends to become worse since then.

⑧ Change of COD

Johoku, Nakatuchido, Sujikai Bridge

Nishiki, Naya, Tennousaki, Matsushige Bridge

Oto, Sumiyoshi Bridge

Atsuta-kinen, Oseko, Kizaemon Bridge

300

May 21th
Ebb tide: 12:10 p.m.
High tide: 19:39 p.m.

Deteriorated
200

Improved

15

100

10

0

5

-100

Tide level・T.P.cm

COD・mg/L

Shiga Bridge, Kita-shimizu Bridgetide level25

20Meoto, Sanage Bridge

-200

0
7

8

9

10

11

12

13

14

15

Note T.P : mean sea level of Tokyo Bay

16

17

18

19

Reference: Japan Meteorological Agency

・COD deteriorated during low tide. It is considered sludge was risen and caused.
・On the middle stream, COD tend to improve during rising tide. It is considered that sea water run up and COD of
sea water was low.

62

River planning department survey group■It is considered that there were a lot of phytoplankton in the middle & downstream.
・Tide level rose and color of surface water got dark blown.
・DO of 20% depth was nearly saturated or oversaturated. The higher tide level, thelarger DO. Especially, the value of Oseko bridge in downstream reached two times ofsaturation value.
・pH of surface was high with rising tide. (=got to alkalinity.)■Blue tide was not seen.
・There was no hydrogen sulfide odor.
・DO of 80% depth remained over three times of saturation value.
Surface Surface layer

Results

20% depth

surface
depth
(m)

ｐＨ

12:48 Oseko B.

2.8

7.6

4

13:30

Sumiyoshi B.

3.0

7.6

14:00

Matsushige B.

2.1

14:30 Naya B.
15:00
15:30

time

location

20% depth

ＣＯＤ visibility(mg/L) (cm)

80% depth

temp.
(℃)

ＤＯ
(mg/L)

ＤＯ
（％）

temp.
(℃)

ＤＯ
(mg/L)

ＤＯ
（％）

50

22.6

9.35

108.1

21.0

4.36

49.1

7

37

22.5

9.07

104.6

21.5

3.82

43.2

7.6

8

27

22.7

7.84

90.8

22.4

6.81

78.5

1.8

7.0

12

38

23.1

10.17

118.8

21.7

3.02

34.4

Matsushige B.

3.7

8.2

10

32

22.2

7.10

81.6

22.2

7.05

81.1

Sumiyoshi B.

3.9

8.4

8

37

22.5

15.45

178.3

21.0

4.12

46.2

16:00 Oseko B.

4.5

8.8

11

18（34）

22.2

17.18

197.7

21.0

5.38

60.4

80% depth
River bottom

63

A lot of phytoplankton exist in water.
photosynthesis …

6CO2+ 6H2O + (Sun) → C6H12O6 + 6O2

Surface

20% depth

14

7.0

pH
6

It is considered that photosynthesis
used CO2, and pH was increased.

0
12:00

13:00

14:00

14

15:00

COD(mg/L)

0
12:00

16:00

10
7

8
6

4

0
12:00

13:00

14:00

15:00

16:00

38

37

40

27

30
10

18
16

7.1

32

37

It is thought to be affected ofphotosynthesis.
13:00

14:00

150
108

105

100

15:00

0
12:00

13:00

14:00

15:00

16:00

4.4

3.8

4.1

3.0

5.4

2
0
12:00

13:00

14:00

15:00

16:00

250
198
178

200

82

150

DO of 30 ～ 80% of
oversaturation wereremained.

100

50

50

0
12:00

0
12:00

14:00

16:00

7.1

6.8

8

15:00

16:00

81

79
49

13:00

15:00

12
10

18

It is thought to be due to increase ofphytoplankton.

14:00

4

16:00

119
91

13:00

DO was remained in bottom.
Small change due to time

14

7.8

DO at Oseko,
250
Sumiyoshi and200
Naya B was
oversaturation.
DO(%)

visibility(cm)50Less change according to place &time.
10・Small different on temperature5
between 20% and 80% depth
15

20

15.5

10.2

9.1

21.5 22.4 21.7 22.2 21.0 21.0

20

6

0
12:00

Transparency of the Oseko B
was deteriorated.

60
50

20

9.4

21.0

0
12:00

16:00
17.2

8

2

100

70

12
10

4

COD was deteriorated.

2

80

15:00

6

4

90

14:00

14

8

8

13:00

20 DO at Oseko B &18
Sumiyoshi B was
16
increased.

1110& timeSmall different on temperature
10
between 20% and 80% depth
15

5

12

12

20 Less change according to place

25

DO(%)

2

DO(mg/L)4

22.5 22.7 23.1 22.2 22.5 22.2

DO(mg/L)

7.6 7.6

Temp.(℃) )

7.6

8

22.6

25

8.8
8.2 8.4

10

Sumiyoshi B.
Oseko B.

30

Temp.(℃) )To alkali

Matsushige B.

80% depth30

12Naya B.

13:00

43

34

14:00

64
46

15:00

60

16:00

The reason why water get alkali due to photosynthesis
CO2 under water balances as below.
CO2 + H2O ⇔ HCO3- + H+
By photosynthesis, hydrogen-carbonate ion （HCO3-） lost CO2, and hydrooxy-ion （ OH- ） was remained,
and then it gets alkali.
HCO3-→CO2＋OHFor CO2 was dissolved in water,
CO2＋H2O→HCO3-＋H+hydrogen ion (H+) was increased and it gets to be acid.

What’s the supersaturation ?
A saturation means that Dissolved Oxygen in water reached a limit(hereafter “saturation value”),
oxygen could dissolve.
A saturation value of DO change according to air pressure, water temperature, dissolved salt ratio, andso on. For example, the saturation value of DO of distillated water under regular air pressure is shown
as below figure.
There is a possibility that water area having a lot of phytoplankton, because many oxygen is released
due to photosynthesis, measured value of DO excesses supersaturation. This situation is called asoversaturation.

DO(mg-O/L)

The correlation between DO and temp of distillated water under 1atom(mg-O/L)

Temp.(degree)65

The state of weather
Kiso River Irrigation Yosui - Water intake from Kiso River was partially restricted
Iwaya Dam- Percentage of storage 52%
Precipitation in Nagoya City- A quarter of annual level

66

Reference: Chunichi Newspaper, Jun 15, 2012, morning edition

⑨The state of peripheral part of salt water
The peripheral part of salt water migrated to upstream

Tide level of
Nagoya Port

Salt water
Reference:Meteorological Agency

Investigation party of River
Planning Division confirmed
the upstream migration of thegarbage from past 16:00 toaround 16:30 at Naya Bridge.

Salt water would be pushed up by the strong
power of upstream migration of spring tide.
It was thought that the peripheral partappeared as a junction line between the salt
water and river water

Nishiki Bridge May 21, 18:20- 18:30

67

Photo by Kawasemi Investigation party

The state of salt water at the dayof the previous partial solar eclipse
At Nishiki Bridge of Horikawa river July 22,2009, 18:45- 18:55

Salt water
The part of salt water is gray and have rotten‐egg smell,and living things seemed to be painful.
=similar to state of blue tides

Why the state of blue tide was notobserved in this annular solar eclipse?

68

Photo by Kawasemi Investigation party

The image of upstream migration of salt
water at the time of the high tide
Peripheral part

Nagoya Port

87

78

100

89

79

50
0
-39

-42

-44

-50
-112

-100

-118

May 21

0

:0 0
18

→←
2012

0: 0

:0 0

0
6: 0

12

0

:0 0
18

May 20

0: 0

:0 0

6: 0

←

12

0

-150
0

It is thought that salt water andfreshwater become the salt-wedge
type at the time of the flood tide ofHorikawa

150

0: 0

Salt water

Freshwater

Tide level of （T.P.cm）

At the time of the high tide of the spring tide, salt
water become strong flows and is pushed up.
At this time, a lump of the fresh water collides headon into a lump of the salt water, and it is thought thatboth water is pushing each other.
It is thought that this becomes the junction line.

→

Reference: Japan Meteorological Agency

Freshwater

Salt
water

Well-mixed type

Freshwater

Partially mixed type

Salt
water

Salt
water

Freshwater

Salt-wedge type

Reference: River erosion control technical standard Report69Reference : image “upstream of salt water
when neap tide”
Nagoya Port

salt
water

strong-mixture

fresh
water

salt
water

medium-mixture

100
51

48

30

50

33

27

-21

0

-30

-45

-56
-50
-100

May 13th ～ May14th, 2012

Data : the Japan Meteorological Agency

salt
water

fresh
water

weak-mixture

Material : standard of river erosion control technology, survey voleme70

5/15 0:00

5/14 18:00

5/14 12:00

5/14 6:00

5/14 0:00

5/13 12:00

5/13 18:00-150
5/13 6:00

It is supposed that salt water andfresh water are weakly mixed whenneap tide in Horikawa river.
fresh
water

150

5/13 0:00

When tide is high in neap tide, upstreaming
force of salt water is not so strong.
Salt water Therefore salt water is not mixed with fresh
water very well and salt water goes underfresh water by heavier specific gravity.

Nagoya Port, tide level (T.P.cm）

Fresh waterMechanism that red tide and blue tide appear
inflow of dirty water（organic substance,
nitrogen, phosphorus)

weather condition(rainfall, temperature,
hours of sunshine)

smell like an addled egg
Hydrogen Sulfide(H2S)
When tide level changes
largely like spring tide, a massof clouded water (part of sulfide

moves upstream.
2H2S + O2 → 2S + 2H2O
2H2S + CO2 + sun → CH2O + 2S + 2H2O

sea water
ＳＯ42（including
sulfate ion)

Horikawa
non smellRiverphytoplankton →photosynthesis
zooplankton

blue tide red tide

react with oxygen and create sulfuric
colloid) including sulfide (mainly
H2S, HS-) is strongly mixed andrain

increasedeath
sinking

Sinking

consuming oxygen withdecomposition of organic substancebacteria that create methane（mostly live in the mud)lack of oxygen

pilled up as sulfide (H２S, S－etc) in the mud and water

sulfate deoxidation bacteria(mostly live in the mud)＊bacteria that like environment without oxygen

When nitrate deoxidation bacteria decompose organic
substance a sulfate ion (SO42-)is deoxidized andhydrogen sulfide(H2S) occur.
SO42- + organic substance → S2- + H2O + CO2
S2- + H+ → HSHS- ＋ H+ → H2S

methane＊bacteria that like environment without oxygen

methane creating bacteria creating
methane with CO２ and H２
4H２ + CO２ → CH４ + 2H２O
・There’re not many anti-salt methane creating
bacteria
・Methane creating bacteria mainly occupy in the areawith few ＳＯ42・Energy source for methane creating
bacteria is H2 that is created with decomposition oforganic substance by other anaerobic bacteria.

71Why didn’t blue tide appear
on the day of annular solar eclipse on May 21st, 2012 ?
Comparison of the data between red tide on May 21st,2012 and blue tide on July 22nd, 2009item

the tide levelchange of tidedifference ofthe tide levelmax (T.P.cm)
min(T.P.cm)max (cm)
min(cm)

total (mm/month)inflow of dirty water

rainfallmax (mm/day)①annular solar eclipse
May 21st, 2012

②solar ecipse
July 22nd, 2009

red tide

blue tide

126
-138
263
89
100
30

≒
≒
≒
≒
＜
＜

on May 15th,long tideincrease of phytoplankton,
zooplankton and the fungi

temprature

ave

(℃)

18

increase of phytoplankton

hours ofsunshineave(hour)

7

124
-145
261
92
262
103

①-②
2
7
2
-3
-162
-73

July 17th,long tide

＜
＞

26

-8

4

3

Data : the Japan Meteorological Agency, surveyed during the previous 30 days

・annular solar eclipse on May 21st, 2012・・・red tide appeared
On six days before that day, it rained 30mm/day during long tide and dirty water flowed into
Horikawa river basin. Then phytoplankton, or red tide, increased by long hours of sunshine. It is
supposed that blue tide didn’t appear because oxygen shortage by consumption of oxygen withdecomposition of organic pollution was not heavy thanks to photosynthesis during daytime.

・solar eclipse on July 22nd 2009 ・・・blue tide appeared
On five days before that day it rained over 100mm/day during long tide andmuch dirty water flowed into Horikawa River basin. It is supposed that blue tide appearedon the midstream and downstream because the basin got under oxygen shortage condition
caused by consumption of oxygen with decomposition of much organic pollution.

72

Annular solar eclipse May 21, 2012
Change of the weather condition and tide levelin the last one month
Tide level …Max tide level:T.P.126cm Min tide level:T.P.-138cm
Difference of tide level …Max value:263cm Min value:89cm

the spring tide

Transitional between
spring tide and neap tide

Annular solar
eclipseRainfall…100mm/month Max value:30mm/day
Mean temperature…18℃ Mean hours of sunshine…7hours

Polluted water inflows
from the sewer

Annular solar
eclipse73

The hours of sunshine were long.

Data: Japan Meteorological Agency

Partial solar eclipse July 22,2009
Change of the weather condition and tide levelin the last one month
Tide level …Max tide level:T.P.124cm Min tide level:T.P.-145cm
Difference of tide level …Max value:261cm
Min value:92cm
the spring tide
Transitional between
spring tide and neap tide

Partial solar
eclipseRainfall…262mm/month Max value:103mm/day
Mean temperature…26℃ Mean hours of sunshine…4hours

Polluted water inflows
from the sewer.

Partial solar
eclipseThe hours of sunshine were short.

74

Data: Japan Meteorological Agency

What kinds of situation make the river hypoxic?
Most of causes of the death fish in Horikawa river are lack of oxygen
We arrange the types of the situation when Horikawa river becomes in short of Oxygen,based on the knowledge about the outbreak of the death fish which Horikawa Sen-nin Chosatai
identified so far.

What was the main cause of the outbreakof the death fish?
・Shortage of Oxygen in Horikawa river

When did a death fish occur?

・From April to June when winter was over,
and water temperature rised
・Spring tide ・After the rain

Data: Japan Meteorological Agency

It has been reported that a lot of sludge, which
has accumulated in the bottom during thewinter, float to the surface with bubbles when
the water temperature rises in the spring.

75

Mass fish deaths in Horikawa River （2007 - 2012）
Sources from website of Nagoya city and Japan Meteorological Agency
Average Precipi
temp-tation(℃) ※ (mm) ※

Date

Tidal
condition

Luna
age

Scene of observation

Cause

Fish
specieslength(cm)

2007/5/28

middle11.3

21

2008/6/23

middle19.3

2010/4/30

spring2010/5/21

bodyamount46

Oseko Brdg - Minatoshin Brdg

Low DOgizzardshad

15～20 1000

2399

Shinsuzaki Brdg - Hataya Brdg

Unknown

goby

5

250

15.6

16

56

Naya Brdg - Hataya Brdg

Low DO

20

150

neap

7.1

20

36

Shiratori Brdg - Minatoshin Brdg, Uchida
Brdg - Horikawa River Confluence

Unknown

20

1500

2011/5/2

spring

28.5

14

104

Shiratori Brdg - Kiraku Brdg

Low DO

2011/5/16

spring

12.8

19

134

Matsushige Brdg

Low DO

2011/5/16

spring

12.8

19

134

AtsutaKinen Brdg - Kiraku Brdg

Low DO

2012/6/19

spring

29.1

21

36

Furuwatari Brdg - Shiratori Brdg

Unknown

gizzardshad
gizzardshad
gizzardshad
gizzardshad
gizzardshad
gizzardshad

remarkdated

20～30 1000
20～30

50

20～30 1500
20～25

rottenrotten200※ survey period : between the previous neap tide and the day①From late April to June.. Average temperature 14 - 23 degrees C (between the previous neap tide and the day)・The organic substance makes layer at the river bottom while the winter for low water temperature. When spring comes, the activityof aerobic microbes increase and oxygen of the river bottom is consumed with biological decomposition of the organic substance.
・The wandering fish go up in Horikawa River such as gizzard shad, mullet and goby in this period.
②After rain falls ... Precipitation amount 36 - 134mm (between the previous neap tide and the day)・Organic substance flows out from rain drainages of combined sewer system, and causes oxygen
consumption.
・Flood stirs organic substance layer on river bottom and spreads it into water.
Bottom sludge comes up③From middle tide to spring tide … Surface water and anoxic water of the bottom get mixed throughto surface in spring.
rising tide, and all water are in a anoxic condition. It may be occurred by high tide. (H24.6.19)④Among midstream – downstream area … Anoxic water can move up by rising tide (creatures lose a refuge).

76Movement of anoxic water
Nagoya Port

Atsutakinen Brg

Kameya Brg
Oto Brg

Upstream

Naya Brg

River becomes narrow
Back current by therising tide

Sulfides in anoxic water mass generate sulfur
colloid and get water clouded.

+ Oxygenfresh water

Anoxic water

salt waterRiver becomes sharrow

Creatures can’t escapefrom anoxic water.

Dead fish flow down stream,and drift with the current.

high tide77

Mass fish deaths in Horikawa River （March – June. 2012）
0

25

20

20

40

15

60

10

80

5
0
2012/3/1

2012/6/19
gizzard shad2012/4/1

2012/5/1

Difference of sea level

100
120

2012/6/1
HighestLowest400

200

High tide by Tropical cyclone No.4

150
tide level （T.P.cm）

mass
fish
death

350

100

300

50

250

0
2012/3/1-50

Precipitation (mm/day)Average temperature200
2012/4/1

2012/5/1

2012/6/1

150

-100

100

-150

50

-200

0

Difference of tide level (cm)Average temperature （℃）

Precipitation30

Sources from website of Nagoya city and Japan Meteorological Agency

84

１１．Progress of Citizen’s Awareness – Activities of Studies

平成24年2月25日(土)第10回堀川1000人調査隊会議 報告：事務局
堀川生物多様性対策会議
平成24年1月26日（木）報告：事務局

第5回堀川まちづくり協議会幹事会 第3回堀川まちづくり協議会
平成24年1月24日（火）平成24年2月14日（火）参加：堀川１０００人調査隊、クリーン堀川など市民団体代表者
報告：事務局

第４回
乙川サミット
平成24年
3月3日（土）発表・報告：事務局
読売新聞
平成24年3月4日(日） 朝刊

第４７回北区地域環境審議会
堀川の生物多様性対策会議の活動について発表
平成24年3月8日（木）堀川１０００人調査隊２０１０実行委員会 梅本隆弘会長
報告：事務局

中日新聞 平成24年5月21日(月） 朝刊

第３回 堀川生物調査
平成24年7月22日（日）85

主催：堀川生物多様性対策会議
報告：御用水跡街園愛護会調査隊
事務局
第２回 堀川生物調査 平成24年5月20日（日）１１．Progress of Citizen’s Awareness – Activities of Studies

猿投橋から黒川樋門までを散策
平成24年4月5日(木)転勤者妻の会 ひまわり
報告：御用水跡街園愛護会調査隊

名古屋城の将来を語る市民大討論会
平成24年2月19日（日）報告：御用水跡街園愛護会調査隊「どう向き合う？外来生物」シンポジウム
平成24年3月10日(土)報告：御用水跡街園愛護会調査隊

御用水跡街園の散策 はぐろ・コミュニティ
平成24年3月24日(土)報告：御用水跡街園愛護会調査隊

黒川樋門でスケッチ
平成24年4月25日（水）名古屋高年大学美術部
報告：御用水跡街園愛護会調査隊
伊勢湾流域圏
再生フォーラム
平成24年3月3日（土）参加：堀川1000人
調査隊2010
報告：事務局
堀川応援隊
名古屋工業大学大学院教授
秀島栄三先生が講演
平成24年7月22日(日)「かわづくり×まちづくり：
名古屋・堀川を中心に」

中川運河再生シンポジウ2012
平成24年8月4日(土)
発表：堀川1000人調査隊
2010事務局
報告：事務局

86

レポート
堀川をいかしたまちづくりを考える
ワークショップ
平成24年3月23日（金）報告： 事務局

１１．Progress of Citizen’s Awareness – Activities of Studies

八熊小学校４年生 堀川総合学習会 平成24年1月27日(金)正木小学校５年生 堀川水質調査
平成24年2月17日(金)飯田小学校３年生 堀川観察会
平成24年5月31日(木)辻小学校２年生 堀川体験学習
平成24年6月4日（月）名北小学校３年生 清掃活動
平成24年6月4日(月)清水小学校２年生 堀川体験学習
平成24年6月12日(火)大杉小学校２年生 堀川体験学習
平成24年6月14日(木)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
河川計画課調査隊、事務局

名北小学校３年生 堀川学習会
平成24年6月15日(金)87１１．Progress of Citizen’s Awareness – Activities of Studies

笹島小学校５年生 堀川観察会
平成24年6月25日（月）名北小学校３年生 堀川観察会
平成24年6月28日（木）支援センターなないろ 堀川探検隊
平成24年6月28日（木）八熊小学校３年生 堀川観察会
平成24年6月29日（金）笹島小学校の親子・近所の親子 川遊び
平成24年7月28日(土)清水小学校の親子 川遊び
平成24年7月30日(月)夏休み親子堀川観察会
平成24年8月17日(金)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
河川計画課調査隊、事務局

八熊小学校５年生 納屋橋空心菜の観察
平成24年7月5日(木)88Progress of Citizen’s Awareness- Activities of “Free Survey Groups” and “Cheering Groups” -中日新聞
平成24年1月19日（日）朝刊

木曽川流域図制作
水源の里を守ろう
木曽川流域みん・みんの会
報告：事務局

第３回 メーク・ア・チェンジ・デー 優秀賞受賞
平成24年2月4日(土)鯱城・堀川と生活を考える会 報告：事務局

平成23年度
活動報告書
平成24年6月13日（水）鯱城・堀川と生活を考える会調査隊

堀川ギャラリーで研究成果発表
平成24年1月31日（火）～2月19日（日）活動報告 平成24年6月29日付
名古屋市高年大学環境学科２５期調査隊「上流は下流を思い、下流は上流に感謝する」「堀川を清流に ９年間を観る 写真とデータ」
水源の里を守ろう 木曽川流域みん・みんの会
報告：事務局
金環日食 堀川一斉調査
平成24年6月6日（水）調査日：5月21日（月）鯱城・堀川と生活
第３回 伊勢湾・三河湾・堀川をきれいにしよう！ を考える会２２期調査隊
北清水橋付近での全国一斉EM団子・EM活性液投入イベント
調査レポート
平成24年7月16日（月・祝）
堀川浄化作戦 黒川樋門にてEM菌を800Ｌ投入
参加：堀川１０００人調査隊 他約220名
編成24年3月14日（水）堀川ＥＭクラブ 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

89

Progress of Citizen’s Awareness- Activities of “Free Survey Groups” and “Cheering Groups” 活動レポート（平成２３年９月～平成２４年２月） 明電舎錦調査隊

中日新聞
平成24年3月16日金） 朝刊

堀川上流部散策 報告書
平成24年7月23日（月）ＷＢＰ堀川応援隊

中日新聞
平成24年4月22日（木）朝刊

90

Progress of Citizen’s Awareness- Activities of “Free Survey Groups” and “Cheering Groups” 空心菜を使った堀川の浄化実験
平成24年6月22日（金）開始
主催：恵那農業高等学校＋名古屋堀川ライオンズクラブ 報告：事務局

堀川ギャラリー「蝶番式ゲート水門」を使っての堀川浄化・展示会開催
平成6月5日（火）～24日（日）鯱城・堀川と生活を考える会調査隊
25期 近藤佑輔氏

中日新聞
平成24年7月12日（木） 朝刊

毎日新聞
平成24年6月19日(火） 朝刊

第５４回 なごや水フェスタ（鍋屋上野浄水場開放デー）
平成24年6月3日（日）堀川１０００人調査隊が堀川浄化をアピール
参加：名古屋市高年大学
環境学科２６期調査隊
名古屋グランパス調査隊
名古屋堀川ライオンズクラブ調査隊

市民の堀川に対する意識調査の結果
名古屋高年大学
環境学科26期

91

Progress of Citizen’s Awareness- Activities of “Free Survey Groups” and “Cheering Groups” -矢野きよ実氏・河村市長 堀川応援隊入隊 平成24年2月4日（土）報告：御用水跡街園愛護会調査隊
横断幕 新調平成24年3月14日（水）協力：黒川ドリーム会、鐵牛応援隊、クロス技研応援隊
環境大臣から
地域環境美化功績者を受賞 黒川ドリーム会
平成24年1月24日（火）報告：事務局

写真家 浅井慎平氏堀川応援隊入隊 平成24年5月10日（木）報告：御用水跡街園愛護会調査隊

なごや北ホームニュース
平成24年3月24日(土）
堀川ギャラリー「ホリゴンのひみつ」展
主催：小林喜春（こばやし・よしはる）氏

定点観測・清掃活動
中日本建設コンサルタント(株)かわせみ調査隊、かもめ応援隊
平成24年6月20日（水）清掃活動
生活支援センターなないろ・ロマン黒川
平成24年2月17日（金）・4月17日（火）報告：御用水跡街園愛護会調査隊

清掃活動 春の堀川一斉大そうじ
平成24年4月21日（土）主催：クリーン堀川
報告：御用水跡街園愛護会調査隊、事務局

92

Progress of Citizen’s Awareness- Activities of “Free Survey Groups” and “Cheering Groups” -清掃活動
春の環境デーなごや
平成24年6月2日（土）北清水親水広場付近
主催：黒川ドリーム会 約２２０名

なごや北ホームニュース
平成24年6月23日(土）

中日新聞
平成24年7月15日(土）
春の環境デーなごや2012
平成24年6月2日（土）堀川体験乗船協力：名古屋堀川ライオンズクラブ
主催：名古屋市環境局

清掃活動 鯱城・堀川清掃大作戦
平成24年7月14日（金）実施：名古屋市高年大学鯱城学園
鯱城学園OB鯱城会
鯱城学園学生会 約770名
報告：御用水跡街園愛護会調査隊

清掃活動
平成24年6月9日（土）ぎふしんムーミン清水支部堀川応援隊

読売新聞
平成24年6月16日(土） 朝刊
清掃活動
鯱城・堀川と生活を考える会
イーツーワン（環境２１期会）

93

活動レポート
環境ボランティアサークル「亀の子隊」

Progress of Citizen’s Awareness –Events–
第５回 木曽三川がつなぐ山とまちインターネットフォーラム
企画・実施：ＮＰＯ法人たからのやま久瀬
堀川１０００人調査隊２０１０実行委員会
平成24年3月25日（日）報告：事務局

岐阜新聞 平成24年3月26日（月）中日新聞 (岐阜総合版） 平成24年3月26日（月） 朝刊

94

黒川友禅流し 平成24年4月7日（土）報告：御用水跡街園愛護会調査隊
事務局

Progress of Citizen’s Awareness –Events–
堀川フラワーフェスティバル2012
開催：平成２４年５月１１日（金）～２６日（土）中日新聞 平成24年5月12日(土） 朝刊

中日新聞
平成24年6月3日（日） 朝刊

中日新聞
平成24年4月27日（金） 朝刊
名古屋市立栄小学校児童

中日新聞 平成24年5月13日（日） 朝刊
市民参加によるハンギングバスケット作り
平成24年4月20日（金）オープニングイベント
堀川の水面上で 「ゴンドラ・ウェディング」
平成24年5月11日（金）報告：御用水跡街園愛護会調査隊

95

堀川を舞台に新作狂言
名古屋堀川ライオンズクラブ調査隊
中日新聞

平成24年7月28日（土） 朝刊

Progress of Citizen’s Awareness –Events–
第８回堀川エコロボットコンテスト
平成24年8月26日（日）主催：名古屋工業大学・名古屋堀川ライオンズクラブ
２４台のロボットが出場 参加者約２００名

ＭＥＭＯ

96