Horikawa Sen-nin Chosatai 2010th

Summary meeting for the 18 stage

The ｓecretariat of Horikawa Sen-nin Chosatai 2010
Feb.6th.2016

Photos：Goyousui-ato-gaien-aigokai
Survey Group
KawasemiSurvey Group1

Horikawa Sen-nin Chosatai 2010
～Transmission of Raw Water from
Kiso Riveｒ～
1.Purpose
To verify the clarification effects of TRWKR with
Citizens(1)Develop to new clarifying measures(2)Asses the influence on an ecosystem(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（from Apr.2007 to Mar.2012）(Including the term of follow-up survey andevaluation 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 ：1st Oct-31St 2010(4)Period of Increased Transmision
Volume :Oct .5th-Nov.2nd 2010

The formation of HSC (April 22nd 2007)
With a viewpoint and a sence of citizens, the survey ofthe clarification effect of TRWKR started■ The survey from a view point and a sence of citizens＊Clearness ＊Transparency ＊Color ＊Smell＊Garbage ＊ Living things ,etc

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 :■ Role of the survey group
April 2007 ～ March 2010(Conclusions of Summary Meeting for the 10th Stage)
Surveys after the stop of TRWKR

Horikawa Sen-nin Chosatai
April 2007～March 2012

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.

■ Fixed Point Observation Groups
Surveying effects of TRWKR■ Free Survey Groups
Researching Horikawa River by free themes■ Horikawa Cheering Groups
Cheering clarification of Horikawa

We improve our plan and take action
against the pollution. After that, citizens
and public administration do what is
possible to clean the river.

The survey from aview point and a
Ts ofsence of citizens

To verify the clarification effectsof 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 wasdeveloped② There 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 removalfrom domestic wastewater and implement
it in each house.

４Water Environment of Horikawa River
Area of basin ：51.9km2
Length ：16.2km
Kiso River is our water source.

Change in temperature, precipitation and length of sunlight
Cause of breedingof phytoplankton,
nitorogen andphosphorus areincluded inwastewater fromhouses, factories
and stores.
It has looked like redtide or blue tide.
In Nagoya Port anddownstream ofHorikawa, it is said
that phytoplankton
does over breedingand extinction, so
water basin ispolluted
rad tide

The primary cause of water pollution is
wastwater from houses,factiories and stores.
Wastwater is discharged after treatment in wastwater treatment plant.
●●●

When heavy rain, wastewater isdischarged without treatment.

●●●

●●●

Shonai River
Provisional raw watertransmission ：0.3m3/s

●●●

●●●

●●●

Wastewater
Treatment Plant

Tide Gate▼high tide●●● ●●●Sanage Bridge

Motoiri Sluiceway

Horikawa▼ebb tide Difference of water level is more than 2m between high tide and edd tide.
Water level, direction of current and velocity are changed by tide.
Nagoya Port

Shimizu wakuwaku-sui

risingGround water etc

Ise bay
Sludge rises and floats.
blue tide

floating sludge

raised sludge

５Method of fixed-point observation
Transparency
Meter
100 cmMeasurement oftransparency

Photo: Shinko Survey Group

What is your
Impression of ・・・
cleanness?
Transparent?
Color?
Bubbles?
Smell?
Garbage?
Living things?

Yurinokai Survey Group
photo:Goyosui-ato-gaien-aigokai
Survey Group

Measurement of COD

Chemical Oxygen Demand. This is
an index of water contamination
used for sea, lakes and marshes.
It is an oxygen consumption
required for oxidation of organic
matters dissolved in ample water.
The higher COD, the more it iscontaminated.

COD pack test

６
Photo: Goyosui-ato-gaien-aigokai Survey GroupInvestigation spots

Network of citizens who wish forclarification and restoration ofHorikawa River is growing.

Number of Participants of Horikawa
Sen-nin Chosatai 2010
(Horikawa Sen-nin Chosatai started
accepting participation on 26th Mar .2007)

Start

Now

22nd Apr.2007

6ｔｈ Feb.2016

Fixed Point
Observation
Groups55 groups
497persons

97 groups
1000persons

Free Survey
Groups22ｇroups
234persons

40 groups
650persons

Horikawa
Cheering
Groups88ｇroups
1,531persons

2,572 groups
51,646persons

Total

165ｇroups
2,262persons

2,709 groups
53,296persons

７

50,000

35,00020,00004/01/07
06/01/07
08/01/07
10/01/07
12/01/07
02/01/08
04/01/08
06/01/08
08/01/08
10/01/08
12/01/08
02/01/09
04/01/09
06/01/09
08/01/09
10/01/09
12/01/09
02/01/10
04/01/10
06/01/10
08/01/10
10/01/10
12/01/10
02/01/11
04/01/11
06/01/11
08/01/11
10/01/11
12/01/11
02/01/12
04/01/12
06/01/12
08/01/12
10/01/12
12/01/12
02/01/13
04/01/13
06/01/13
08/01/13
10/01/13
12/01/13
02/01/14
04/01/14
06/01/14
08/01/14
10/01/14
12/01/14
02/01/15
04/01/15
06/01/15
08/01/15
10/01/15
12/01/15
02/01/16

Number of Participants

Number of Participants ofHorikawa Sen-nin Chosatai
Growth of participants

60,00055,000

FPOG

2st

1st
4st

3st
6st

5st
7st

FSG

25,000

8st
9st

HCG

10st
11st

Total

Total53,296人

45,000
Fixed Point Observation Groups(FPOG)1,000person

40,000Free Survey Groups(FSG)650person

Horikawa Cheering Groups(HCG)51,646person

30,000

12st
14st

13st
16st

15st

February 6th 2016

18st

17st

15,00010,0005,000

0month and year８

Survey Period and Number of Reports
With TRWKR

Introduceds
shallow
groundwater

Introduction of advanced water
treatment the Meijo Water
Teatmemnt Centre
In-service of Horikawa
Ugan Rain-Water Reservoir
for pollution control

Increase of
Transmisson Volume
from the Shonai River
Utilization of reclamedwastewater from Moriyama
Water Treatment Centre
from Apr. to Oct

Covered
Sand

Total

1st stageinterval
2nd stageinterval
3rd stageinterval
4th stageinterval
5th stageinterval
6th stageinterval
7th stageinterval
8th stageinterval
9th stageinterval
10th stage
interval
11th stage
interval
12th stage
interval
13th stage
interval
14th stage
interval
15th stage
interval
16th stage
interval
17th stage
interval
18th stage

Survey Period
Spring - Early Summer / Apr. 22nd - Jun. 30th. 2007
Jul. 1st - Sep. 7th. 2007
Autumn - Early Winter / Sep. 8th -Dec. 16th. 2007
Dec. 17th - Mar. 31st. 2008
Spring - Early Summer / Apr. 1st - Jun. 30th. 2008
Jul. 1st - Sep. 27th. 2008
Autumn - Early Winter / Sep. 28th -Dec. 16th. 2009
Dec. 17th. 2008 - Mar. 31st. 2009
Spring - Early Summer / Apr. 1st - Jun. 30th. 2009
Jul. 1st - Sep. 26th. 2009
Autumn - Early Winter / Sep. 27th -Dec. 16th. 2009
Dec. 17th. 2009 - Mar. 31st. 2010
Spring - Early Summer / Apr. 1st - Jun. 30th. 2010
Jul. 1st - Sep. 11th. 2007
Autumn - Early Winter / Sep. 12th -Dec. 17th. 2010
Dec. 18th. 2010 - Mar. 31st. 2011
Spring - 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. 2012
Spring - Early Summer / Apr. 1st - Jun. 30th. 2012
Jul. 1st - Sep. 21th. 2012
Autumn - Early Winter / Sep. 22th -Dec. 16th. 2012
Dec. 17th. 2012 - Mar. 31st. 2013
Spring - Early Summer / Apr. 1st - Jun. 30th. 2013
Jul. 1st - Sep. 28th. 2013
Autumn - Early Winter / Sep. 29th -Dec. 17th. 2013
Dec. 18th - Mar. 31st. 2014
Spring - Early Summer / Apr. 1st - Jun. 30th. 2014
Jul. 1st - Sep. 7th. 2014
Autumn - Early Winter / Sep. 28th -Dec. 16th. 2014
Dec. 17th. 2014 - Mar. 31st. 2015
Spring - Early Summer / Apr. 1st - Jun. 30th. 2015
Jul. 1st - Sep. 19th. 2015
Autumn - Early Winter / Sep. 20th -Dec. 16th. 2015

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
128
4,132

９

Number of Reports

The total number of survey reports is 4,132 by the end of the18thstage. On average, it is 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.

１０

４．Weather Condition

Mean monthly temperature

There were many sunny days in the end of Sep.. However, it was raining
hard from 24th to 26th as it was influenced by an atmospheric depression
with an autumn rain front moving eastward on the southern sea.
The temperature had been low in the first half of Oct. due to an inflow ofcold air mass from China. In the latter half of Oct. the temperature had
been high because the warm air mass overlay Nagoya. In Oct. there weremany sunny days covered, little rain and a lot of hours of sunlight by highatmospheric pressure.
Because low and high atmospheric pressure passed alternately, theweather changed every few days in Nov. There were a few of sunny days
and a large amount of rainfall with a lot of rainy and cloudy days under the
influence of a low atmospheric pressure and an autumn rain front. Besides,
an influence of the cold air mass was weak, hot weather continued.
In Dec. An influence of the cold air mass from North was weak, an mean
monthly temperature was 9.3℃.

(Nagoya Local Meteorological Agency)

Dec 2015：9.3℃

average value (Nagoya Local Meteorological Agency)

18th Stage(from Sep. to Dec. 2015)
Weather condition■Temperature
A mean temperature was 16.3℃ which is above average(15.4℃)■Precipitation
In Sep. we had a lot of rain due to an atmospheric depression
with an autumn front. In contrast, There were little rain in Oct,and Dec. The mean precipitation is 137mm/month which ishigher than the average(121.9mm/month)■Sunlight hours
There were many sunny days and a lot of hours of sunlight inOct. Therefore, monthly mean sunlight hours is 177, which ismore than average.

(mm)
total

temperature(℃)
average
high

1981
～2010

1981
～2010

30
124.8
156.5
201.0
160.8
234.4
128.3
79.7
45.0
121.9

30
14.4
18.9
22.7
18.7
24.1
18.1
12.2
7.0
15.4

low

sunlight(hours)
total

1981
～2010

1981
～2010

1981
～2010

30
19.9
24.1
27.2
23.7
28.6
22.8
17.0
11.6
20.0

30
9.6
14.5
19.0
14.4
20.7
14.1
8.1
3.1
11.5

30
196.6
197.5
149.9
181.3
151.0
169.0
162.7
172.2
163.7

Nagoya Local Meteorological Agency
http://www.jma.go.jp/jma/menu/report.html

11

precipitation

sectionperiod
year
Apr.
May
Jun.

Average
Sep.
Oct.
Nov.
Dec.

AverageChange of Temperature

Nagoya Local Meteorological Agency
http://www.jma.go.jp/jma/menu/report.html

Spring to Early Summer(Apr.～Jun.)

Autumn to
early winter30

Mean value : 18.7℃
temperature(℃)

25
20

18.7

19.1

19.5

18.6

18.7

18.6

18.9

19.4

19.6

16th stage

15

18th stage

10

In 18th stage, from the latter
half of Oct, the temperature
had been high because thewarm air mass overlay
Nagoya.

5temperature

15th stage

13th stage

11th stage

9th stage

7th stage

7th stage

5th stage

3rd stage

1st stage

0

Autumn to Early Winter(Sep.～Dec.)
30

Mean value : 15.4℃

25
20

16.4

15.9

15.8

16.4

16.1

15.4

15.8

15.2

16.3

15

A mean temperature of 18th stage was
16.3℃ which is above average(15.4℃）

10
516th stage

14th stage

14th stage

12th stage

10th stage

8th stage

6th stage

4th stage

0
2nd stage

temperature(℃)

14th stage

12

Chagne of precipitation

Nagoya Local Meteorological Agency
http://www.jma.go.jp/jma/menu/report.html

Monthly mean value166.8mm

Monthly mean value121.9mm

In Sep. we had a lot of rain due to an atmospheric depression with an autumn
front. In contrast, There were little rain in Oct, and Dec. The mean precipitation
is 137mm/month which is higher than the average(121.9mm/month)13

Change of hours of sunlight

Nagoya Local Meteorological Agency
http://www.jma.go.jp/jma/menu/report.html

Monthly mean value181.3hours

Monthly mean value163.7hours

There were many sunny days and a lot of hours of sunlight in Oct.
Therefore, monthly mean sunlight hours is 177, which is more than
average.

14

５．Main Measures for Water Quality Improvementfy. 2007
Measuresfy. 2008

1st.

fy. 2009

3st.
2st.

fy. 2010

5st.
4st.

fy. 2011

7st.
6st.

fy. 2012

9st.
8st.

11st.
10st.

12st.

fy. 2013

fy. 2014

fy. 2015

13st.

15st.

17st.

14st.

16st.

18st.

With TRWKR(0.4m3/s)
Build a deep and shallow zone
（Improvement of self-purification
function and water enironment)
Increase of raw water transmission
from the Shonai River(＋0.4m3/s)
Utilization of shallow ground water(0.0405m3/s)
Experiment of covering sand forwater purification Gojo Brdg.-Naka
Brdg.（water's edge along both banks）
Introduction of Advanced water
treatment at the Meijo Water
Treatment Center
In-service of the Horikawa Ugan
Rain-water Reservoir for pollution
control
Utilization of reclaimed wastewater atMoriyama Water Treatment
Center(0.046m3/s)

Newly launched facilities after the stop of TRWKR■For improvement of quality of treated water(Additional filtration of treated water at the Meijo
Water Treatment Center can improve quality of water
discharging into Horikawa River )Advanced water treatment
at Meijo Water Treatment Center
Solution : conventional activated sludge
process and rapid filtration
Launch : May. 2010

■For improvement of combined sewer system(Storing first flush with high pollution load torestrain outflows temporarily)

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

Construction of water storage facility for
improvement of combined sewer system
Legendcompleted
under construction

15

Newly launched facilities after the stop of TRWKR■Securement of Additional Water Resource
Utilization of Reclaimed wastewater（冬場を除く）Conducting reclaimed wastewater treated bymembrane filtration at the Moriyama Water
Treatment Center (up to 4000m3/day) isdischarged

Moriyama Water
Treatment CenterStart
to conduct
in Aug. 2011
通水開始
平成23年8月

Shonai
Irrigation

Conducting point into
Horikawa River

Reclaimed wastewater is conductedduring irrigation season (Apr - Oct)

Horikawa
River
Reference： 17th Horikawa Sennin Chosatai conference

16

■Form of shallow and deep spot

Common indian kingfisher, little egret, turtle

Downstream from Kurokawa No.2 Bridge Sep.2013

Carp, Crucian carp,
Hemibarbus barbus
Goby minnow

Pale chubAmur goby

Young pale
chub

Stone
masonry

Shrimp, crab, aquatic insect

the self-cleansing action by food chain
Pollution（organic substance・Nitrogen・phosphorus, etc）
Algae and microbes are spread by pollution
Fish, shrimp, insects eat algae, microbes

Various living things
come to this place
for growing andbreeding.

Big fish and birds eat small fish and insects
Waterside,
Surface ofwater

Reeves’ turtle
In water Slider
Common Indian
Kingfisher,
Black-crawned
Carp, Hemibarbus barbus,
night heron
Catfish, Black buss, Bluegill
Northern snake head

Prawn andJapanese mitten
crab migrate
between river andsea.

Reference： 10th Horikawa Sennin Chosatai conference

Crucian carp, Pale chub,
Goby minnow, Amur goby,
Mosquitofish
Palaemon adspersus,
Prawn, Japanese mittencrab, Aquatic insect17

■ Purification experiment by sand cover
started in June 2015

■Utilization of shallow ground water
A well at an upstream of Shiga Bridge
operated in Mar.2015

Photo:
http://horimachi.blog.fc2.com/

18

５．Relation between tidal level and water quality
The survey we made before shows that the sludge is exposed and rolled up in a tidal section, between the mouth of Horikawa and Sanage
Bridge, when the tidal level drops. And those movements of sludge affect impression of water clearness. In the 18th stage, we analyzed therelation between the tidal level in the Nagoya Port and the water quality of Horikawa in detail.
The result shows different tendency about “Impression of clearness” between Sanage Bridge ～ Asahi Bridge section and Asahi Bridge ～Matsushige Bridge section. Specifically impression of clearness is better when the tidal level is low than when it’s high between Sanage
Bridge and Asahi Bridge. And Impression is evaluated by transparency when the tidal level is low. On the other hand, impression of clearness
is a little worse when the tidal level is low than when it’s high between Asahi Bridge and Matsushige Bridge. The impression is mainly
evaluated by water color, and as the tidal level become lower and lower, evaluation by smell is more and more but evaluation bytransparency is less and less. We guess those relations are affected by an exposure and rolling up of sludge.
Relation between the tidal level and the water quality is important to improve the impression of clearness at each section.

dirty

cleaｎ

mainly evaluatedby water color

dirty

clean

mainly evaluatedby transparency
dirtyslightly dirty ordinary slightly clean clean

dirty slightly dirty ordinary slightly clean clean

mainly evaluatedby water color
smell：decreasetransparency：increasegarbage：increase

mainly evaluatedby water colersmell：increasetransparency：decreasegarbage：decrease

exposure of sludge
with smell

18th,May, 2015
Tidal level is 130cm T.P.

deep site→no transparency

shallow site→transparency

raising up of sludge
with smell andno transparency

bubbleswith smell

25

Improvement of natural purification
by food chain is expected.

６．Purification experiment by sand cover (started in February, 2015)
It has been almost a year since the purification experiment by sand cover started
between Naka Bridge and Gojo Bridge as a new measure for purification.
We suspected that “covering sand and purification materials will be flowed away”
or “ they will be covered with black sludge” when Nagoya City authority told they
start that experiment at the 14th meeting. Therefore we started periodical
observation to confirm the experiment process as soon as the experiment started.
We can find cover sand and purification materials on the bridge today, a year
passed since the experiment started. In particular, we can find even grains ofwhite sand at the section covered with sand.
In addition, a large variety of animal has been found in the experiment section.
For example, kinds of duck stayed, looked for foods and took something like analga in their mouth in the 18th stage. We can’t tell what they eat actually, but wecan find ducks which is looking for foods more at the site covered withpurification materials (coal ash) than the site covered with sand. We don’t know
the reason yet.

Sand-covered section Dec. 10th, 2015teal
purification materials-covered
sectionWhat kind of living things live andthrive at the sand-covered area?

Birds(river edge)
・water wagtail
・starling・phoenicurus・turtledove・rock dove・carrion crow・little egret
・halcyon

W
A
T
E
R
S
Birds(aquatic)

・spot-billed dock・dabchick・mandarin duck・tufted duck・teal・mallard
・cormorant

Reptile・red eared sliderfish・mosquitofish
・carp
・northern snakehead・mulletGrains of sand can be seenin the sand-covered section

26

６.２. Impression of water clearness■ Which is your impression of Today’s Horikawa?
Dirty？ Slightly dirty？ Ordinary？
Slightly clean？ Clean？
■ By which are you impressed?
Color？ Smell？ Transparency? Litters？
Bubbles? Living Things?

Source: 14th HSC report, p.15（revised and edited partly)

Transparency improve→see riverbed→impression become better？
Observe

Observe

Observe

Transparency low

water

water

water

riverbed

riverbed

riverbed

Transparency highwhite colored riverbed

Report：Horikawa Cheering Group(Sato Family)
2016.Jan.1 Nakatsuchido Bridge
First time ever wehave seen such atransparent water(morning in Jan. 1st )black colored riverbed

Report：Secretariat
2016.Jan.4 Naya Bridge

Report：Secretaiiat
2016. Jan.12 Naya Bridgetransparency was highat Naya Bridge(afternoon in Jan. 4th)27

stage ： With TRWKR
Impression of Water Clearness (average in each section)１st～6th
No rain on the day and the previous day

Ratio of “Clean”～“Ordinary”** exceptthe data between Oseko Bridge and Minatoshin Bridge for not enough data
TRWKR

7th～18th stage：No TRWKRNo rain on the day and the previous day

Form of pool and shoal
Utilization of shallow groundwater
Increasing of transmission from Shonai River
Covering sand etc.
Introduction of advanced water treatment at Meijo Water Treatment Center
In-service of Horikawa Ugan Rain-water Reservoir for pollution controlｌ

Utilization of reclaimed wastewater at Moriyama Water Treatment Center

Section

Sakae Bridge～
Sanae Bridge

Unit：％
39

93

87

50

87

100

60

100

100

100

100

100

75

100

100

100

100

100

16

57

43

73

53

36

29

62

40

39

23

20

50

30

56

73

58

70

（small number of data）

Sanage Bridge～
Johoku Bridge
Johoku Bridge～
Asahi Bridge

Tend to Improve8（small number of data）

38

36

50

23

50

TRWKR
→Tend to improve or sustain

0

20

12

42

21

25

14

27

40

67

50

62

Red or Blue tide andcurling up of sludge etc.
occurred →Worsen

Stop of TRWKR→Worsen or sustain

Asahi Bridge～
Matsushige Bridge

11

39

23

57

21

25

0

28

5

37

28

21

12

20

24

31

24

53

Matsushige Bridge～
Oseko Bridge

27

45

12

56

18

56

6

61

16

54

22

20

20

50

3

62

100

57

1st.

2st.

3st.

4st.

5st.

6st.

7st.

8st.

9st.

10st. 11st. 12st. 13st. 14st. 15st. 16st. 17st. 18st.

％（dirty）％（cleaｎ）＊“Clean”, “Slightly clean” and “Ordinary” are categorized as the acceptable range for citizens.

Impression of water clearness, especially between Sanage and Asahi Bridge, is considered to tend to improve little bylittle by the effect of newly conduted water quality improvement measures as well as the change of citizen’s awareness.

28

Impression of water clearness

１st～6th stage ： With TRWKRNo rain on the day and the previous day
7th～18th stage：No TRWKRNo rain on the day and the previous day

Ratio of “Clean”～“Ordinary”*

Upstream section（Sakae～Sanage Bridge_Ave.）

TRWKR

Form of pool and shoal
Increasing of transmission from Shonai River

Utilization of shallow groundwater
Covering Sand etc.

Introduction of advanced water treatment at Meijo Water Treatment Center

In-service of Horikawa Ugan Rain-water Reservoir for pollution controlｌ
Utilization of reclaimed wastewater at Moriyama Water Treatment Center

25 of the 31 surveys were done at Kizune
Bridge on Jun. 27th, many of them were“slightly dirty”.

Sakae Bridge 栄橋～猿投橋間～ Sanage Bridge
100

100

100

100

100

100

100

100

100

100

100

93
87

87
75

80

60
60

40

50

Horikawa upstream section:
Generally acceptable for citizens

39（ratio of “Clean”～“Ordinary” was almost 100%)

20

Numberof Survey

H27.9.20～12.16

H27.4.1～6.30

H26.9.29～12.16

H26.4.1～6.30

H25.9.29～12.17

H25.4.1～6.30

H24.9.22～12.16

H24.4.1～6.30

H23.9.11～12.16

H23.4.1～6.30

H22.9.11～12.17

H22.4.1～6.30

H21.9.27～12.16

H21.4.1～6.30

H20.9.28～12.16

H20.4.1～6.30

H19.9.8～12.16

0
H19.4.22～6.30

水の汚れの印象（％）
Impression ofwater clearness(%)

100

第1st. 第2st. 第3st. 第4st. 第5st. 第6st. 第7st. 第8st. 第9st. 第10st. 第11st. 第12st. 第13st. 第14st. 第15st. 第16st. 第17st. 第18st.

31

41

15

2*

8*

3*

5*

8*

5*

9*

9*

＊small number of data
■ How did impression of water clearness change in the upstream section(between Sakae Bridge andSanage Bridge)?
Although number of data was small, ratio of “clean”～“ordinary” was almost
100%. Impression of water clearness changes mostly in the acceptable range for citizens.

8*

8*

7*

7*

1*

4*

4*

＊“Clean”, “Slightly clean” and “Ordinary”
are categorized as the acceptable range
for citizens.

29

Impression of water clearness* except

１st～6th stage ： With TRWKRNo rain on the day and the previous day
7th～18th stage：No TRWKRNo rain on the day and the previous day

Ratio of “Clean”～“Ordinary”*

the data between Oseko Bridge and Minatoshin Bridge for not enough data

Mid・Downstream section（Sanage～Oseko Bridge_average）

TRWKR

Form of pool and shoal
Increasing of transmission from Shonai River

Utilization of shallow groundwater
Covering Sand etc.

Introduction of advanced water treatment at Meijo Water Treatment Center“Clean”, “Slightly clean” and“Ordinary” are categorized as
the acceptable range forcitizens.

In-service of Horikawa Ugan Rain-water Reservoir for pollution controｌ
Utilization of reclaimed wastewater at Moriyama Water Treatment Center

猿投橋～大瀬子橋間
SanageBridge ～ Oseko Bridge

29

29

24

22

24

18

16

32

31

42

61％

H27.9.20～12.16

43

H27.4.1～6.30

20

43

42

61

58

H26.4.1～6.30

40

H25.4.1～6.30

45

H24.9.22～12.16

60

H25.9.29～12.17

After TRWKR
Worsened

59

Improved

Increasing occurrenceof bubbles and smell,
Going upstream of red
tide and blue tide,
Winding up ofsludge →Worsened

H24.4.1～6.30

80

With TRWKR
Improved

9

H21.9.27～12.16

H22.4.1～6.30

H22.9.11～12.17

第3st.
176

第4st.
52

第5st.
111

第6st.
63

第7st.
85

第8st.
67

H26.9.29～12.16

H21.4.1～6.30

第2st.
208

H23.9.11～12.16

H20.9.28～12.16

第1st.
113

H23.4.1～6.30

H20.4.1～6.30

Numberof調査数
SurveyH19.9.8～12.16

0

H19.4.22～6.30

Impression of水の汚れの印象（％）
water clearness(%)

100

第9st. 第10st. 第11st. 第12st. 第13st. 第14st. 第15st. 第16st. 第17st. 第18st.
76
98
62
90
113
89
77
113
93
81

■ How did the impression of water clearness change in the middle and downstream of Horikawa River (between Sanage Brdg. and Oseko Brdg.)? →Improving
trend was seen (the ratio of “Clean”, “Slightly clean” and “Ordinary” was increased) during TRWKR. In the 7th stage after the stop of TRWKR, impression ofwater clearness was worsened. Moreover, in the 12th and 13th stage, it was worsened by increasing occurrence of bubbles and smell, going upstream of red
tide and blue tide, and winding up of sludge. However, impression of water clearness was improved after that. It is considered that these trends are made by
the effect of new water quality improvement measures. The ratio of “Clean”, “Slightly clean” and “Ordinary” was 61% in the 18th stage.

30

Impression of water clearness（Average）・・・Spring～Early Summer

１st, 3rd, 5th stage ： With TRWKRNo rain on the day and the previous day
7th, 9th, 11th, 13th, 15th, 17th stage：No TRWKRNo rain on the day and the previous day

Ratio of “Clean”～“Ordinary”
Improved between Sanage and Oseko Bridge

100

improved

80
60

53

56

50

43

58

40

40
20

29

23

16

0
H19.4.22～
6.30

H20.4.1～
6.30

H21.4.1～
6.30

H22.4.1～
6.30

第1st.
第3st.
第5st.
第7st.
第1ｓｔ.
第3ｓｔ.
第5ｓｔ.
第7ｓｔ.

Number37
of survey

42

30

24

H23.4.1～
6.30

H24.4.1～
6.30

H25.4.1～
6.30

H26.4.1～
6.30

H27.4.1～
6.30

第9st.
第11st. 第13ｓｔ.
第13st. 第15ｓｔ.
第15st.
第17st.
第17ｓｔ.
第9ｓｔ.
第11ｓｔ.

20

27

16

16

12

80

Going upstream of red tide and blue tide,60

worsened

40

23
20

H19.4.22～
6.30

80

Going upstream of red tide and blue tide,

worsened
36

40

23
8

50
40

14

0

0
H19.4.22～
6.30

21
12

H20.4.1～
6.30

H21.4.1～
6.30

H22.4.1～
6.30

第1st.
第3st.
第5st.
第7st.
第1ｓｔ.
第3ｓｔ.
第5ｓｔ.
第7ｓｔ.
Number14
13
6＊
of survey 12

H23.4.1～
6.30

H24.4.1～
6.30

H25.4.1～
6.30

H26.4.1～
6.30

H27.4.1～
6.30

第9st.
第11st. 第13ｓｔ.
第13st. 第15ｓｔ.
第15st.
第17st.
第17ｓｔ.
第9ｓｔ.
第11ｓｔ.

9＊

14

H21.4.1～
6.30

H22.4.1～
6.30

H23.4.1～
6.30

24

H24.4.1～
6.30

H25.4.1～
6.30

H26.4.1～
6.30

H27.4.1～
6.30

Matsushige
Bridge～Oseko Bridge
松重橋～大瀬子橋＊small number of data60

H20.4.1～
6.30

24
12

5

0

0

improved

第1st.
第3st.
第5st.
第7st.
第9st.
第11st.
第13st.
第15st. 第17ｓｔ.
第17st.
第1ｓｔ.
第11ｓｔ.
第15ｓｔ.
第3ｓｔ.
第13ｓｔ.
第5ｓｔ.
第7ｓｔ.
第9ｓｔ.
Number
43
82
35
37
25
22
34
29
of survey 46

7＊

5＊

6＊

水の汚れの印象（％）
Impressionof water clearness(%)

Impression水の汚れの印象（％）
of water clearness(%)

100

28

21

11

Johoku城北橋～朝日橋
Bridge～Asahi Bridge

20

Asahi Bridge～Matsushige Bridge
朝日橋～松重橋

100
Impression of水の汚れの印象（％）
water clearness(%)

水の汚れの印象（％）
Impressionof water clearness(%)

猿投橋～城北橋
Sanage Bridge～Johoku
Bridge100
80

Going upstream of red tide and blue tide,

worsened

60
40

Less than 50% （bad）
27

20

12

18

16

improved
36

22

20

6

3

0
H19.4.22～
6.30

H20.4.1～
6.30

H21.4.1～
6.30

H22.4.1～
6.30

H23.4.1～
6.30

H24.4.1～
6.30

H25.4.1～
6.30

H26.4.1～
6.30

H27.4.1～
6.30

第1st.
第3st.
第5st.
第7st.
第9st.
第11st. 第13ｓｔ.
第13st. 第15ｓｔ.
第15st. 第17ｓｔ.
第17st.
第3ｓｔ.
第5ｓｔ.
第7ｓｔ.
第9ｓｔ.
第11ｓｔ.
Number 第1ｓｔ.
of survey 15
27
30
33
35
29
30
25
34

■ How did the impression of water clearness change in each section (spring to early summer)?
Impression of water clearness (Sanage Bridge～Oseko Bridge) was improved after the stop of
TRWKR. The ratio of “Clean”, “Slightly clean” and “Ordinary” (Sanage Bridge ～Asahi Bridge)was
improved to more than 50%. However, it was under 50% (bad) between Asahi Bridge to Oseko
Bridge, need to be improved.

“Clean”, “Slightly clean” and “Ordinary” are categorized as theacceptable range for citizens.
Less than 50% ratio of “Clean”, “Slightly clean” and “Ordinary”
is categorized as “bad” , and less than 20% as “especially
bad”.

31

With TRWKRNo rain on the day and the previous day

Evaluation of Impression of water clearness ・・・Spring～Early Summer
Sanage Bridge ～ Johoku Bridge
0%

20%

40%

60%

1st stage

100%

1st stage: no survey

3rd stage

730

7th stage

17

21

15

25

7

“transparency”increased

40%

40

3rd stage

30

5th stage

53

7th stage

58

9th stage

58

11th stage

58

24

27
16

56

44

20%

1st stage

50

50

0%

Number ofsurvey20

33

60

15th stage

4

30

30

“color” decreased

13th stage

10
23

40

58

11th stage

13

39

38

5th stage

9th stage

Asahi Bridge～Matsushige Bridge

80%

13th stage

8

100%
Number ofsurvey

5

23

23

19

11

23

9

63

17th stage

14

9

57

“"smell"”decreased
3

69

4 24

8

13

17

“color” increased

11 3 37

19

14

21 82

18

13

5

61

15th stage

67

25

80%

1st stage: no survey

16

17th stage

60%

22
43
35

19

9

17

3 3 3 2932

12

①Color②Smell③Transparency④Litters⑤Bubble⑥Living things ⑦Others①Color②Smell③Transparency

0%

20%

Johoku Bridge～Asahi Bridge
0%

20%

40%

1st stage
65

5th stage

70

7th stage

11th stage①Color②Smell

100%

11

33

14
17

20

③Transparency⑤Bubble

80%

100%

15

13

5th stage

17

6*

7th stage

9*

9th stage

59

8

14

11th stage

59

15

6*

13th stage

74

6 6

11 3 35

5*

15th stage

70

18

9 3 346*

17th stage

21

50④Litters

60%

3rd stage

80
50

40%

14

17

33

⑦Others

1st stage

33

65⑥Living things

Number ofsurvey21

50
56

13th stage

7
15

33

9th stage

17th stage

7⑤BubbleMatsushige Brige～Oseko Bridge

80%

1st stage: no survey

3rd stage

15th stage

60%④Litters⑥Living things＊small number of data
⑦Others①Color②SmellNumber ofsurvey1st stage: no survey

7

72
3

23

48

33
③Transparency

30④Litters⑤Bubble

3 33

15

3

79

7

14

28

3 3 3020

4 4 24

25

4 27

22

37

30

⑥Living things⑦Others

Note: 0% item isn’t displayed■ How did the evaluation of impression water clearness(spring ～ early summer) in each sections change?
→Between Sanage Brdige and Johoku Bridge, ”Color” decreased and “Transparency” increased after the stop of
TRWKR. On the other hand, between Asahi Bridge and Matsushige Bridge, “Color” increased and “Smell” decreased.
Transparency was improved between Sanage Bridge and Johoku Bridge because of improved transparency.

32

Impression of water clearness（Average）・・・Autumn～Early Winter2nd, 4th, 6th stage ： With TRWKRNo rain on the day and the previous day
8th, 10th, 12th, 14th, 16th, 18th stage：No TRWKRNo rain on the day and the previous day

Ratio of “Clean”～“Ordinary”

Improved between Sanage and Matsushige Bridge 朝日橋～松重橋
Asahi Bridge～Matsushige Bridge
朝日橋～松重橋間

Improved

60

73

73

80

62

57

39

36

40

H19.9.8～
12.16

worsened 30

H20.9.28～ H21.9.27～ H22.9.11～ H23.9.11～ H24.9.22～ H25.9.29～ H26.9.29～ H27.9.20～
12.16
12.16
12.17
12.16
12.16
12.17
12.16
12.16

第2st.
第4st.
第6st.
第2ｓｔ.
第4ｓｔ.
第6ｓｔ.

Numberof
調査数
surveyIncreasing occurrence of bubbles andsmell, Going upstream of blue tide

20

20
0

70

47

11

17

16

23

20

17

11

20

水の汚れの印象（％）
Impressionof water clearness(%)

100＊small number of data
Increasing occurrence of bubbles
67
and smell, Going upstream blue tide

60
40

50

50

Number ofsurvey
調査数

worsened
25

20

20
0

42

38

62

27

40

21

2*

第6st.
第6ｓｔ.

4*

第8st.
第10st.
第12st. 第14ｓｔ.
第14st. 第16ｓｔ.
第16st.
第18st.
第8ｓｔ.
第18ｓｔ.
第10ｓｔ.
第12ｓｔ.

5*

12

12

11

6*

8*

worsened

39

37
25

28

0

H19.9.8～
12.16

53

31
21

20

20

H20.9.28～ H21.9.27～ H22.9.11～ H23.9.11～ H24.9.22～ H25.9.29～ H26.9.29～ H27.9.20～
12.16
12.16
12.17
12.16
12.16
12.17
12.16
12.16

第2st.
第4st.
第6st.
第8st.
第10st.
第12st.
第14st.
第16st.
第18st.
第6ｓｔ.
第2ｓｔ.
第4ｓｔ.
第8ｓｔ.
第16ｓｔ.
第18ｓｔ.
第10ｓｔ.
第12ｓｔ.
第14ｓｔ.

Number of
調査数
survey

103

28

16

25

43

40

松重橋～大瀬子橋
松重橋～大瀬子橋間
Matsushige Bridge～Oseko
Bridge
100

60

25

29

32

＊small number of data

Increasing occurrence of bubbles
and smell, Going upstream blue tide

80

56

56

61

worsened
54

62

50

45

57

40

20

20

H20.9.28～ H21.9.27～ H22.9.11～ H23.9.11～ H24.9.22～ H25.9.29～ H26.9.29～ H27.9.20～
12.16
12.16
12.17
12.16
12.16
12.17
12.16
12.16

第2st.
第4st.
第2ｓｔ.
第4ｓｔ.

Increasing occurrence of bubbles
and smell, Going upstream blue tide

57

60

0
H19.9.8～
12.16

Improved

80

第8st.
第10st.
第12st.
第14st. 第16ｓｔ.
第16st. 第18ｓｔ.
第18st.
第8ｓｔ.
第10ｓｔ.
第12ｓｔ.
第14ｓｔ.

城北橋～朝日橋
Johoku Bridge～Asahi
Bridge
城北橋～朝日橋間
80

100
Impression of水の汚れの印象（％）
water clearness(%)

100

水の汚れの印象（％）
Impressionof water clearness(%)

水の汚れの印象（％）
Impressionof water clearness(%)

猿投橋～城北橋
Sanage Bridge～Johoku
Bridge
猿投橋～城北橋間

Number ofsurvey
調査数■ How did the impression of water clearness change in each section (autumn to early winter)?
Impression of water clearness between Sanage Bridge and Matsushige Bridge was improved after
the stop of TRWKR. The ratio of all sections were over 50% at the 18th stage.

H19.9.8～
12.16

H20.9.28～ H21.9.27～ H22.9.11～ H23.9.11～ H24.9.22～ H25.9.29～ H26.9.29～ H27.9.20～
12.16
12.16
12.17
12.16
12.16
12.17
12.16
12.16

第2st.
第2ｓｔ.

第4st.
第6st.
第8st.
第10st. 第12ｓｔ.
第12st.
第14st. 第16ｓｔ.
第16st.
第18st.
第6ｓｔ.
第4ｓｔ.
第8ｓｔ.
第18ｓｔ.
第10ｓｔ.
第14ｓｔ.

35

9*

25

21

35

26

28

16

30

“Clean”, “Slightly clean” and “Ordinary” are categorized as theacceptable range for citizens.
Less than 50% ratio of “Clean”, “Slightly clean” and “Ordinary” iscategorized as “bad” , and less than 20% as “especially bad”.

33With TRWKRNo rain on the day and the previous day

Evaluation of Impression of water clearness ・・・Autumn～Early WinterSanage Bridge ～ Johoku Bridge
0%

20%

40%

60%

2nd stage

21

53

4th stage

18

55

6th stage

27

12th stage

30

9

11

4th stage

5 5

50

15

16
22
20

24

17

8

“transparency”over 50%②Smell③Transparency

0%

20%

④Litters⑤Bubble

40%

38

3

25

10

⑥Living things⑦Others

6th stage

69

8th stage

64

10th stage

2nd stage

65

4th stage

550

8th stage
50

12th stage①Color②Smell50
75

14th stage

18th stage

25
100

10th stage

55

25
27

9

33

9

67
57

③Transparency

29④Litters⑤Bubble32 98 survey

36

28

8

10

15

60

3

“color”decreased50②Smell6

1276

18th stage

Number of28

14th stage

100%

30

75

27

3

16

16

25

16

43

28

40

20

4 25

34

3 29

“transparency”increased25

19③Transparency ④Litters ⑤Bubble

3 32⑥Living things ⑦Others

Matsushige Bridge ～ Oseko Bridge

80%

50

6th stage

16th stage

60%

100%

25

47

Johoku Bridge～Asahi Bridge
40%

80%

27

56

12th stage①Color60%

39

16th stage
20①Color

20%

12

55

35

17

58

75

17

18th stage

2nd stage

6

29

47

16th stage

9

56

5

0%

Number of
47 survey

12

29

5

14th stage

9

9

38

10th stage

100%

17

59

8th stage

Asahi Bridge～Matsushige Bridge

80%

14

0%

20%

40%

60%

80%

Number of
20 survey

2nd stage

2*

4th stage

4*

6th stage

5*

8th stage

12

10th stage

12

12th stage

68

4

11

14th stage

63

10

6*

16th stage

7*

18th stage＊small number of data
⑥Living things ⑦Others①Color②Smell

53

36

44

28

12

48

37

9

50

17

13
3

25

19

31

19

12

③Transparency ④Litters ⑤Bubble

21

6
16

24
25

20

Number ofsurvey

9*

36

14

30

11

56

52
19

100%

25

3 29
13

27

35

16
30

⑥Living things ⑦Others

Note: 0% item isn’t displayed■ How did the evaluation of impression water clearness(autumn～early winter) in each sections change?
→Ratio of “transparency”(Sanage Bridge～Johoku Bridge) was almost more than 50% after the stop of TRWKR.
“Color” was decreased and “Transparency” was increased between Asahi Bridge and Matsushige Bridge.

34

6.3 Transparency
Survey of transparency

photo:Shinko Survey Group

Relation between impression of clearness
and transparency
・2nd stage ～ 18th stage, No rain, including data outside
the specified period
・evaluated by clarity
・in all sections including upstream data“clean～ordinary” is defined to citizen’s
acceptable valuetransparency level
over 70cm
photo:Goyosuiato Gaien Aigo Chosatai

citizen’s acceptable value oftransparency level is over 70cm

39

1st ～ 6th stage ： With TRWKRNo rain on the day and the previous day
7th ～ 18th stage ： No TRWKRNo rain on the day and the previous day

Change of transparency （section average）
Except the data between Oseko Bridge and Minatoshin Bridgefor not enough data

With TRWKR

Creation of deep water and rapids
Utilization of shallow groundwater
Increasing volume of transmission water from Shonai River Covering sandIntroduction of advanced water treatment at Meijo Water treatment CenterIn- service of Horikawa Ugan Rain-water reservoir for pollution control
Utilization of reclaimed wastewater at Moriyama Water Treatment Center(Survey section)
Unit ： cm

Sakae Bridge～
Sanage Bridge

57

80

63

59

42

88

55

62

55

64

67

86

71

79

85

100

71

88

Sanage Bridge～
Johoku Bridge

58

80

71

87

68

79

58

77

64

67

63

75

66

75

65

82

68

84

Johoku Bridge～
Asahi Bridge

59（a few data）

improvement
74

52

45

61

65

54

57

50

56

56

74

51

75

92

52

79

65

77

60

78

57

77

60

85

65

86

56

83

54

95

56

83

57

87

48

81

58

85

56

95

54

81

3st.

4st.

5st.

6st.

7st.

8st.

9st.

59

89

1st.

2st.

Matsushige Bridge～
Oseko Bridge

57

60

61

53

51

90

84

Asahi Bridge～
Matsushige Bridge

50

after TRWKR
worsened or kept

with TRWKR
improvement or kept

（a few data）

43

10st. 11st. 12st. 13st. 14st. 15st. 16st. 17st. 18st.

cm

Transparency has a tendency to be improved Between Sanage Bridge and Asahi Bridge
mainly in the stage from autumn to early winter. We think it’s an effect of the New measures
for water quality improvement after TRWKR.

cm
citizen’s acceptablevalue of transparency
level is over 70cm

40

1st ～ 6th stage ： With TRWKRNo rain on the day and the previous day
7th ～ 18th stage ： No TRWKRNo rain on the day and the previous day
Upstream section （between Sakae Bridge and Sanage Bridge, average)

Change of transparency

Creation of deep water and rapids
Utilization of shallow groundwaterWith TRWKR

Covering sandIncreasing volume of transmission water from Shonai River
Introduction of advanced water treatment at Meijo Water treatment CenterIn- service of Horikawa Ugan Rain-water reservoir for pollution control
Utilization of reclaimed wastewater at Moriyama Water Treatment Center

100
100

88

86

80

79

Transparency(cm)
透視度(cm)

80

63
60

88

85

57

64

62

59

55

71

71

67

after 12th stage, over 70cm

55

42
40

20

第9st. 第10st. 第11st. 第12st. 第13st. 第14st. 第15st. 第16st. 第17st. 第18st.

3*

41

13

2*

8*

3*

5*

8*

5*

8*

7*

7*

1*

4*

H27.9.20～12.16

第8st.

H27.4.1～6.30

第7st.

7*

H26.9.29～12.16

第6st.

H26.4.1～6.30

H22.9.11～12.17

第5st.

9*

H25.9.29～12.17

H22.4.1～6.30

第4st.

H25.4.1～6.30

H21.9.27～12.16

第3st.

9*

H24.9.22～12.16

H21.4.1～6.30

第2st.

H24.4.1～6.30

H20.9.28～12.16

H23.9.11～12.16

H20.4.1～6.30

第1st.

H23.4.1～6.30

H19.9.8～12.16

Numberof data

H19.4.22～6.30

04** not enough data
■Change of transparency in the upstream section, between Sakae Bridge and Sanage Bridge,
There are not enough data, but transparency level in 12th stage was over 70cm.

citizen’s acceptablevalue of transparency
level is over 70cm

41

Change of transparency
Middle and downstream section （between Sanage Bridge andOseko Bridge)
With TRWKR

1st ～ 6th stage ： With TRWKRNo rain on the day and the previous day
7th ～ 18th stage ： No TRWKRNo rain on the day and the previous day

Creation of deep water and rapids
Utilization of shallow groundwater
Covering sandIntroduction of advanced water treatment at Meijo Water treatment CenterIn- service of Horikawa Ugan Rain-water reservoir for pollution control
Utilization of reclaimed wastewater at Moriyama Water Treatment Center

100

82

improved or kept
76

Transparency(cm)
透視度(cm)

80

60

72
61

60

57

worsened
Just after TRWKR

83

73 *

72
59

52

improved 84

kept after TRWKR

60

59

58 *

56

82

73

over 80cm
about 60cm
at 16th and 18th stage
from spring to early summer (from autumn to early winter)40

20

H27.9.20～12.16

64

H27.4.1～6.30

第8st.

77

H26.9.29～12.16

第7st.

61

H26.4.1～6.30

H22.9.11～12.17

第6st.

95

H25.9.29～12.17

H22.4.1～6.30

第5st.

36

H25.4.1～6.30

H21.9.27～12.16

第4st.

129

H24.9.22～12.16

H21.4.1～6.30

第3st.

155

H24.4.1～6.30

H20.9.28～12.16

第2st.

55

H23.9.11～12.16

H20.4.1～6.30

第1st.

H23.4.1～6.30

H19.9.8～12.16

Numberof data

H19.4.22～6.30

0

第9st. 第10st. 第11st. 第12st. 第13st. 第14st. 第15st. 第16st. 第17st. 第18st.

73

108

107

84

90

81

■How did the transparency change in the middle and downstream section （Sanage Bridge ～ Oseko Bridge)?
It was tend to be improved with TRWKR and worsened after TRWKR.
It was kept at about 60cm from Spring to early Summer and over 70cm from Autumn to early Summer after
TRWKR, and improved to over 80cm after the 16th stage.
＊The blue tide, red tide and raising up of sludge were found in the12th and 13th stage but they don’t affectvery much. We think it’s because we sampled surface fresh water.

79

54

74

89

“citizen’s acceptablevalue of transparency
level is over 70cm

42

1st, 3rd, 5th stage : With TRWKRNo rain on the day and the previous day
7th, 9th, 11th, 13th, 15th, 17th stage : No TRWKRNo rain on the day and the previous day

Change of transparency
section average, from Spring to early Summer

Sanage Bridge～ Johoku Bridge Improved between Sanage Bridge
猿投橋～城北橋

透視度(cm)Transparency(cm)

80
60

71

improved
68

58

58

64

63

66

65

68

40

透視度(cm)Transparency(cm)100Bridge
and Matsushige

100

H19.4.22～ H20.4.1～
6.30
6.30

H21.4.1～
6.30

第1st.
第3st.
第1ｓｔ.
第3ｓｔ.

第5st.
第7st.
第9st. 第11ｓｔ.
第11st. 第13ｓｔ.
第13st. 第15ｓｔ.
第15st. 第17ｓｔ.
第17st.
第5ｓｔ.
第7ｓｔ.
第9ｓｔ.

13

32

26

H22.4.1～
6.30

19

H23.4.1～
6.30

20

H24.4.1～
6.30

26

H25.4.1～
6.30

16

H26.4.1～
6.30

60

16

12

Numberof data

60

65

60

52

60

57

65

61
52
43

51

54

50

56

51

40

透視度(cm)Transparency(cm)＊not enough data
8059

H19.4.22～ H20.4.1～
6.30
6.30

H21.4.1～
6.30

第1st.
第3st.
第1ｓｔ.
第3ｓｔ.

第5st.
第7st.
第9st. 第11ｓｔ.
第11st. 第13ｓｔ.
第13st. 第15ｓｔ.
第15st. 第17ｓｔ.
第17st.
第5ｓｔ.
第7ｓｔ.
第9ｓｔ.

22

56

29

H22.4.1～
6.30

22

H23.4.1～
6.30

H24.4.1～
6.30

41

20

H25.4.1～
6.30

H26.4.1～
6.30

33

H27.4.1～
6.30

27

27

58

56

54

H25.4.1～
6.30

H26.4.1～
6.30

H27.4.1～
6.30

Matsushige
Bridge ～ Oseko Bridge
松重橋～大瀬子橋

100

100

80
60

59

56

54

56

57

H21.4.1～
6.30

H22.4.1～
6.30

H23.4.1～
6.30

48

40
20

20

0

0

H19.4.22～ H20.4.1～
6.30
6.30

H19.4.22～ H20.4.1～ H21.4.1～ H22.4.1～ H23.4.1～ H24.4.1～ H25.4.1～ H26.4.1～ H27.4.1～
6.30
6.30
6.30
6.30
6.30
6.30
6.30
6.30
6.30
第1st.
第3st.
第1ｓｔ.
第3ｓｔ.

Numberof data

53

61

40

H27.4.1～
6.30

JohokuBridge ～ Asahi Bridge
城北橋～朝日橋Transparency(cm)
透視度(cm)

80

0

0

60

improved

20

20

Numberof dataAsahi
Bridge ～ Matsushige Bridge
朝日橋～松重橋

9*

9*

第5st.
第7st.
第9st. 第11ｓｔ.
第11st. 第13ｓｔ.
第13st. 第15ｓｔ.
第15st. 第17ｓｔ.
第17st.
第5ｓｔ.
第7ｓｔ.
第9ｓｔ.

11

6*

9*

14

7*

5*

5*

Numberof data

H24.4.1～
6.30

第1st.
第3st.
第5st.
第7st.
第9st.
第11st. 第13ｓｔ.
第13st. 第15ｓｔ.
第15st. 第17ｓｔ.
第17st.
第1ｓｔ.
第3ｓｔ.
第5ｓｔ.
第7ｓｔ.
第9ｓｔ.
第11ｓｔ.

11

32

29

The transparency from spring to early summer is tend to be improved between Sanage Bridge andMatsushige Bridge but that level is under 70cm. It is 68cm between Sanage Bridge and Johoku
Bridge, only 2cm below citizen’s acceptable level.

30

24

26

34

31

citizen’s acceptablevalue of transparency
level is over 70cm

30

43

2nd, 4th, 6th stage : With TRWKRNo rain on the day and the previous day
8th, 10th, 12th, 14th, 16th, 18th stage : No TRWKRNo rain on the day and the previous day

Change of transparency
section average, from Autumn to early WinterTransparency(cm)
透視度(cm)

100
80

80

87

79

77

improved
67

75

Improved between Sanage Bridge Asahi
朝日橋～松重橋
Bridge ～ Matsushige Bridge
and Matsushige
Bridge
100
92
90
75

82

84

60
40
20
0

Numberof data

80

77

78

77

H22.9.11～12.17

H23.9.11～12.16

H24.9.22～12.16

H25.9.29～12.1785

86

H26.9.29～12.16

H27.9.20～12.1660
40

H19.9.8～12.16

H20.9.28～12.16

H21.9.27～12.16

H22.9.11～12.17

H23.9.11～12.16

H24.9.22～12.16

H25.9.29～12.17

H26.9.29～12.16

第2st.
第4st.
第6st.
第8st. 第10ｓｔ.
第10st. 第12ｓｔ.
第12st. 第14ｓｔ.
第14st. 第16ｓｔ.
第16st. 第18ｓｔ.
第18st.
第6ｓｔ.
第8ｓｔ.
第2ｓｔ.
第4ｓｔ.

35

8*

17

16

23

18

17

12

0

H27.9.20～12.1620

Numberof dataH19.9.8～12.16

65

60

50

45

57

57

74

75

56

40

透視度(cm)Transparency(cm)＊not enough data

H21.9.27～12.16

74

18

16

22

30

40

24

松重橋～大瀬子橋
Matsushige
Bridge ～ Oseko Bridge
10074

H20.9.28～12.16

第2st.
第4st.
第6st.
第8st.
第10st. 第12ｓｔ.第14ｓｔ.
第12st.
第14st. 第16ｓｔ.
第16st. 第18ｓｔ.
第18st.
第6ｓｔ.
第8ｓｔ.
第2ｓｔ.
第4ｓｔ.
第10ｓｔ.

城北橋～朝日橋
JohokuBridge ～ Asahi Bridge
Transparency(cm)
透視度(cm)

79

20

100
80

improved

84

透視度(cm)Transparency(cm)

猿投橋～城北橋
Sanage Bridge～ Johoku Bridge

89

95

83

83

87

81

21

29

95

85

81

80
60
40
20

20

＊not enough data0

Numberof data0
H19.9.8～12.16

H20.9.28～12.16

H21.9.27～12.16

H22.9.11～12.17

H23.9.11～12.16

H24.9.22～12.16

H25.9.29～12.17

H26.9.29～12.16

H27.9.20～12.16

第2st.
第4st.
第6st.
第8st.
第10st.
第12st.
第14st.
第16st.
第18st.
第6ｓｔ.
第8ｓｔ.
第2ｓｔ.
第4ｓｔ.
第18ｓｔ.
第16ｓｔ.
第10ｓｔ.
第12ｓｔ.
第14ｓｔ.

16

1*

3*

5*

12

11

11

6*

6*

H19.9.8～12.16

H20.9.28～12.16

H21.9.27～12.16

H22.9.11～12.17

H23.9.11～12.16

H24.9.22～12.16

H25.9.29～12.17

H26.9.29～12.16

H27.9.20～12.16

第2st.
第4st.
第6st.
第8st.
第10st.
第12st.
第14st.
第16st.
第18st.
第6ｓｔ.
第8ｓｔ.
第2ｓｔ.
第4ｓｔ.
第16ｓｔ.
第18ｓｔ.
第10ｓｔ.
第12ｓｔ.
第14ｓｔ.

Numberof data

30

9*

The transparency is tend to be improved and that level is over 70cm between Sanage Bridge andMatsushige Bridge from autumn to early winter.

25

21

33

25

29

15

citizen’s acceptablevalue of transparency
level is over 70cm

30

44

６.４. ＣＯＤ
Chemical Oxygen Demand. It means degree of water pollution by organic
substance in the sea, lakes and marshes mainly. It is volume of oxygen which
react on organic substance in water.

COD pack test
How to test
Reagent is ina tube.
Pick here andpull out.

1. Pull plug out.

2. Put air out.

3. Absorb waterfrom intake hole.

4. Compare the color withcheck sheet,after 5 minutes .

45

1st – 6th stage : With TRWKRNo rain on the day and the previous day
7th – 18th stage : No TRWKRNo rain on the day and the previous day(not enough data)

Change of COD (average in some sections)
Section between the Minatoshin Bridge and the Oseko Bridge is excepted

New water quality improvement measure by Nagoya City

With TRWKR

Making of diversionary flow

Utilization of groundwater
Coverage the sludge with clarification materials

Raw Water Transmission from the Shonai River

Introduction of advanced water treatment at Meijo Water Treatment Center
Service of Horikawa Ugan Rainwater Reservoir for pollution control
Utilization of reclaimed wastewater from Moriyama Water Treatment Center《Section》▼ Stop of TRWKR

mg/L

Sakae Bridge–
Sanage Bridge

16

10

9

9

9

9

8

15

7

(not enough data)

Sanage Bridge –Johoku Bridge
Johoku Bridge –Asahi Bridge

14

9

9

9

10

9

11

13

11

15

13

11

10

12

9

12

12

9

(not enough data)

15

Matsushige Bridge –Oseko Bridge

11

11

14

8

14

13

7

5

new water quality improvement measure
after
the
stop
of TRWKR
9
12
11
8
13
8
12
10
9
→ slightly improved

10

slightly worsened
after the stop of TRWKR

with TRWKR

Asahi Bridge –Matsushige Bridge

13

10

12

11

10

15

10

10

8

a little fluctuation or kept
after the stop of TRWKR

11

13

11

12

13

13

11

12

11

13

10

14

10

12

10

8

7

9

6

8

8

9

7

9

9

11

7

12

9

9

7

3st.

4st.

5st.

6st.

7st.

8st.

9st.

11

14

10

10

1st.

2st.

10st. 11st. 12st. 13st. 14st. 15st. 16st. 17st. 18st.

Stage
COD

mg/L

mg/L

We think that the COD readings have been better between the Sanage Bridge and the Asahi Bridge
mainly because of effect by new water quality improvement measure after the stop of TRWKR.

46

Change of COD（average between the Sakae Bridge and the Sanage Bridge)《Upstream section》

1st – 6th stage : With TRWKRNo rain on the day and the previous day
7th – 18th stage : No TRWKR
Change of COD No rain on the day and the previous day

Making of diversionary flow
Utilization of groundwater
Raw Water Transmission from the Shonai River

With TRWKR

Coverage the sludge with clarification materials

Introduction of advanced water treatment at Meijo Water Treatment Center
Service of Horikawa Ugan Rainwater Reservoir for pollution control
Utilization of reclaimed wastewater from Moriyama Water Treatment Center

Stop of TRWKR ▼ new water quality improvement measure after the stop of TRWKR

slightly improved

Numberof survey

5*

18

13

6*

9*

6*

5*

8*

5*

9*

9*

7*

8*

7*

7*

1*

4*

4*

*: Not enough data

■ How did COD change in the upstream section (between the Sakae Bridge and the Sanage Bridge)→ COD is over 10mg/L more frequently after 8th stage. It was below 10mg/L in the 17th and 18th
stage.

47

Change of COD（average between the Sanage Bridge and the Oseko Bridge)《Middle and downstream section》

1st – 6th stage : With TRWKRNo rain on the day and the previous day
7th – 18th stage : No TRWKR
Change of COD No rain on the day and the previous day

Making of diversionary flow
Utilization of groundwater
Raw Water Transmission from the Shonai River

With TRWKR

Coverage the sludge with clarification materials

Introduction of advanced water treatment at Meijo Water Treatment Center
Service of Horikawa Ugan Rainwater Reservoir for pollution control
Utilization of reclaimed wastewater from Moriyama Water Treatment Center

improved or kept
with TRWKR**

slightly worsened
after the stop of TRWKR

a little fluctuation or kept
after the stop of TRWKR

new water quality improvement measure after the stop of TRWKR
slightly improved

Numberof survey

115

182

152

76

101

87

84

63

75

112

109

85

92

82

84

61

■How did COD change in the middle and downstream section (between the Sanage Bridge and the Oseko Bridge)?
→ It seems that COD was improved and kept during TRWKR, slightly worsened after the stop of TRWKR. It was fluctuated or
kept around 10mg/L in the 13th and 15th stage, and was improved after the 16th stage.
In the 12th and 13th stage, going up of blue tide or red tide and rising of sludge was reported, but the effect of those didn’t
appear clearly because it supposed that we observed fresh water of a surface.

74

89

48

1st,3rd,5th stage : With TRWKRNo rain on the day and the previous day
7th,9th,11th,13th,15th ,17th stage : No TRWKRNo rain on the day and the previous day

Change of COD (spring – early summer)
20
18
14

16

14

13

12

10

9

10

11

11

12

improved
9

10

8

14

13

12

12

13

12

13

14
12

10
8
6

4

4

2

2
0

0
H19.4.22～6.30

H20.4.1～6.30

H21.4.1
～6.30

第1ｓｔ.
第1st.
第3st.
第3ｓｔ.
Number 43
of survey

H22.4.1～6.30

H23.4.1～6.30

H24.4.1～6.30

H25.4.1～6.30

H26.4.1
～6.30

31

24

20

27

16

16

H19.4.22～6.30

H20.4.1～6.30

H21.4.1
～6.30

第1st.
第3st.
第1ｓｔ.
第3ｓｔ.
Number 38
60
of survey

第5st.
第5ｓｔ.

H27.4.1
～6.30

第5st.
第7st.
第9st.
第11st. 第13ｓｔ.
第13st. 第15ｓｔ.
第15st.
第17st.
第17ｓｔ.
第5ｓｔ.
第7ｓｔ.
第9ｓｔ.
第11ｓｔ.

45

20

12

20

城北橋～朝日橋
JohokuBridge – Asahi Bridge
not enough data

15

14

11

12

12

12
9

10

10

11

15

improved
10

12
10
6
4

2

2

0
第1st.
第3st.
第1ｓｔ.
第3ｓｔ.

Number 15
of survey

16

H22.4.1～6.30

H23.4.1～6.30

H24.4.1～6.30

H25.4.1～6.30

H26.4.1～6.30

H27.4.1
～6.30

第5st.
第7st.
第9st.
第11st.
第13st. 第15ｓｔ.
第15st.
第17st.
第17ｓｔ.
第5ｓｔ.
第7ｓｔ.
第9ｓｔ.
第11ｓｔ.
第13ｓｔ.

12

6*

9*

14

7*

5*

H25.4.1～6.30

6*H26.4.1～6.30

H27.4.1
～6.30

第7st.
第9st.
第11st. 第13ｓｔ.
第13st.
第15st. 第17ｓｔ.
第17st.
第7ｓｔ.
第9ｓｔ.
第11ｓｔ.
第15ｓｔ.

22

24

42

35

33

26

worsened
11

10

9

8

8

4

H21.4.1～6.30

H24.4.1
～6.30

14

6

H20.4.1～6.30

H23.4.1
～6.30

16

8

H19.4.22～6.30

29

H22.4.1～6.30

松重橋～大瀬子橋
Matsushige
Bridge – Oseko Bridge

18

COD(mg/L)

18

COD(mg/L)

15

14

6

16

朝日橋～松重橋
Asahi Bridge– Matsushige Bridge

18

COD(mg/L)

COD(mg/L)

16

20

猿投橋～城北橋
SanageBridge – Johoku Bridge

8

9

9

H23.4.1～6.30

H24.4.1
～6.30

12
9

0
H19.4.22～6.30

H20.4.1～6.30

H21.4.1～6.30

H22.4.1
～6.30

第1st.
第3st.
第1ｓｔ.
第3ｓｔ.

第5st.
第5ｓｔ.

第7st.
第9st.
第11st.
第13st.
第15st.
第17st.
第17ｓｔ.
第7ｓｔ.
第9ｓｔ.
第11ｓｔ.
第15ｓｔ.
第13ｓｔ.

Number 19
of survey

31

29

COD from spring to early summer was likely to keep the same status or be improved slightly.

30

24

26

H25.4.1～6.30

34

H26.4.1～6.30

30

H27.4.1
～6.30

30

49

2nd,4th,6th stage : With TRWKRNo rain on the day and the previous day
8th,10th,12th,14th,16th,18th stage : No TRWKRNo rain on the day and the previous day

Change of COD (autumn – early winter)
20

20

Sanage猿投橋～城北橋
Bridge – Johoku Bridge

18

16

14
12

9

9

12

9

improved

11
9

8

8

8

6

12

H22.9.11～12.17

H23.9.11～12.16

H24.9.22～12.16

H25.9.29～12.17

H26.9.29～12.16

第2st.
第4st.
第6st.
第8st.
第10st.
第12st.
第14st.
第16st.
第18st.
第6ｓｔ.
第8ｓｔ.
第2ｓｔ.
第4ｓｔ.
第16ｓｔ.
第18ｓｔ.
第10ｓｔ.
第12ｓｔ.
第14ｓｔ.
18
17
20
20
12
24
16
23
Number 54
of survey

20

13

12

12
10

10

9

10

10

improved
8

12
10

4

2

2
0
H22.9.11～12.17

H23.9.11～12.16

H24.9.22～12.16

H25.9.29～12.1730

H22.9.11～12.17

H24.9.22～12.1610

10

H25.9.29～12.17

H26.9.29～12.16

H27.9.20～12.16

第6ｓｔ.
第6st.
第8st.
第10st.
第12st.
第14st.
第16st.
第18st.
第8ｓｔ.
第18ｓｔ.
第16ｓｔ.
第10ｓｔ.
第12ｓｔ.
第14ｓｔ.
21

25

43

31

25

29

32

H26.9.29～12.16

H27.9.20～12.16

第2st.
第4st.
第6st.
第8st.
第10st.
第12st.
第14st.
第16st.
第18st.
第6ｓｔ.
第8ｓｔ.
第2ｓｔ.
第4ｓｔ.
第16ｓｔ.
第18ｓｔ.
第10ｓｔ.
第12ｓｔ.
第14ｓｔ.
Number 21
11
11
6*
6*
9*
5*
12
8*
of survey

worsened

10
7

8

4

H21.9.27～12.16

H23.9.11～12.161014

6H20.9.28～12.1611

16

6

H19.9.8～12.1611

松重橋～大瀬子橋
Matsushige
Bridge – Oseko Bridge

18

8

0

H21.9.27～12.1620

12
10

H20.9.28～12.16

Number 70
of survey

not enough data

16

H19.9.8～12.16

第2st.
第4st.
第2ｓｔ.
第4ｓｔ.

城北橋～朝日橋
JohokuBridge – Asahi Bridge

18
14

0

H27.9.20～12.1611

62

H21.9.27～12.1611

8
4

H20.9.28～12.1611

10

2
H19.9.8～12.16

improved

13

14

4
0

COD(mg/L)

COD(mg/L)

13

COD(mg/L)

COD(mg/L)

16

10

朝日橋～松重橋
Asahi Bridge– Matsushige Bridge

18

H19.9.8～12.16

H20.9.28～12.168
6

H21.9.27～12.16

H22.9.11～12.179
7

H23.9.11～12.169
7

H24.9.22～12.16

H25.9.29～12.17

7

H26.9.29～12.16

H27.9.20～12.16

第2st.
第4st.
第6st.
第8st.
第10st. 第12ｓｔ.
第12st. 第14ｓｔ.
第14st. 第16ｓｔ.
第16st. 第18ｓｔ.
第18st.
第6ｓｔ.
第8ｓｔ.
第2ｓｔ.
第4ｓｔ.
第10ｓｔ.

Number 37
of survey

20

33

17

34

25

COD from autumn to early winter was improved between the Sanage Bridge and the Matsushige Bridge. It was improved to
8mg/L especially between the Sanage Bridge and the Johoku Bridge.

29

14

29

50

6.5.Bubbles

Near Nishiki Bridge
Most Bubbles float from riverbottom, and some of thembring black bottom sludge.

Bubbles from river bottom inmovie “This is bottom of
Horikawa River” recorded in2008.05.01-05
Falling water may cause
many bubbles.

Sanage Bridge

Situation with many bubbles

Situation with a few bubbles

51

1st -6th stage ： With TRWKRNo rain on the day and the previous day
7th -17th stage ： No TRWKRNo rain on the day and the previous day

Change of Bubbles from River Bottom*except data from Minato-shin bridge to Oseko bridge

With TRWKR

Form of pool and shoal
Utilization of groundwater
Bottom sediment covering
Introduction of advanced water treatment at Meijo Water Treatment Center

Increase of raw water transmission from Shonai River

In-service of Horikawa Ugan Rain-water Reservoir for pollution control
Utilization of reclaimed wastewater at Moriyama Water Treatment Center(estimating period)
単位：％
Sakae Brdg – Sanage Brdg
（less data number）

25

3

33

50

13

0

0

0

0

0

0

0

0

0

0

0

0

0

Sanage Brdg – Johoku Brdg

21

6

19

0

11

6

32

13

20

13

36

25

31

6

13

17

22

13

40

17

After stopping TRWKR
In improving a little
Johoku Brdg – Asahibashi Brdg
（less data number）

8

5

0

8

0

0

0

With TRWKR
In improving

10

0

17

21

0

0

20

0

Less data number

No TRWKR
Worsen a little

30

42

0

38

13

58

12

18

35

40

0

31

7

24

19

3

0

0

0

14

0

13

3

8

0

7

0

5

0

0

5

3st.

4st.

5st.

6st.

7st.

8st.

9st.

58

23

56

Matsushige Brdg – Oseko Brdg 7
1st.

3

2st.

Asahi Brdg – Matsushige Brdg

0%10st. 11st. 12st. 13st. 14st. 15st. 16st. 17st. 18st.
%

Bubbles from river bottom tend to improve a little in spite of stopping TRWKR. We guess recent
measures for water quality improvement work.

52

Bubbles from River Bottom

Upstream(Average between
Sakae Brdg to Sanage Brdg)
栄橋～猿投橋間Bubblesreported(%)

With TRWKR

100

Form of pool and shoal
Utilization of groundwater
Bottom sediment covering
Increase of raw water transmission from Shonai River
Introduction of advanced water treatment at Meijo Water Treatment Center
In-service of Horikawa Ugan Rain-water Reservoir for pollution control

80

Utilization of reclaimed wastewater at Moriyama Water Treatment Center

60
50
40

Upstream of Horikawa River
After 6th stage
No bubbles from river bottom was reported

33
25

20

13
3

0

0

0

0

0

0

0

0

0

0

0

0

0

H26.9.29～12.16

H26.4.1～6.30

H26.9.29～12.16

H26.4.1～6.30

H25.9.29～12.17

H25.4.1～6.30

H24.9.22～12.16

H24.4.1～6.30

H23.9.11～12.16

H23.4.1～6.30

H22.9.11～12.17

H22.4.1～6.30

H21.9.27～12.16

H21.4.1～6.30

H20.9.28～12.16

H20.4.1～6.30

H19.9.8～12.16

0

H19.4.22～6.30

泡の発生状況_泡が川底から浮いてくる割合(%)

1st -6th stage ： With TRWKRNo rain on the day and the previous day
7th -17th stage ： No TRWKRNo rain on the day and the previous day

第1st. 第2st. 第3st. 第4st. 第5st. 第6st. 第7st. 第8st. 第9st. 第10st. 第11st. 第12st. 第13st. 第14st. 第15st. 第16st. 第17st. 第18st.
Numberof data

24

38

15

2*

8*

3*

5*

8*

5*

9*

9*

8*

8*

7*

7*

1*

4*

4*

*less data number
How did bubbles from river bottom change in upstream of Horikawa river?
Though number of data is not enough, no bubbles was reported after 6th stage.

53

Bubbles from River Bottom

Mid-Downstream(Average between
Sanage Brdg to Oseko Brdg)
猿投橋～大瀬子橋間

Bubblesreported(%)

With TRWKR

Form of pool and shoal

100

Utilization of groundwater
Increase of raw water transmission from Shonai River
Bottom sediment covering
Introduction of advanced water treatment at Meijo Water Treatment Center
In-service of Horikawa Ugan Rain-water Reservoir for pollution control
Utilization of reclaimed wastewater at Moriyama Water Treatment Center

80

60

40
24

Improving trendwith TRWKRHigh temperatureworsened the condition.

worsen

25

21

20

21

15

20
9

8

7

19

After stopping TRWKR, state of
bubbles slightly improved
22

20

17

7

2

14
6

2

Numberof data

H26.9.29～12.16

H26.4.1～6.30

H26.9.29～12.16

H26.4.1～6.30

H25.9.29～12.17

H25.4.1～6.30

H24.9.22～12.16

H24.4.1～6.30

H23.9.11～12.16

H23.4.1～6.30

H22.9.11～12.17

H22.4.1～6.30

H21.9.27～12.16

H21.4.1～6.30

H20.9.28～12.16

H20.4.1～6.30

H19.9.8～12.16

0

H19.4.22～6.30

泡の発生状況_泡が川底から浮いてくる割合(%)

1st -6th stage ： With TRWKRNo rain on the day and the previous day
7th -17th stage ： No TRWKRNo rain on the day and the previous day

第1st. 第2st. 第3st. 第4st. 第5st. 第6st. 第7st. 第8st. 第9st. 第10st. 第11st. 第12st. 第13st. 第14st. 第15st. 第16st. 第17st. 第18st.
105

206

167

47

97

59

82

63

73

108

100

94

87

75

72

59

58

72

How bubbles from river bottom change in mid-downstream of Horikawa river?
After stopping TRWKR, stat of bubbles got slightly improved throughout effects of recent measures forwater quality improvement.

54

1st -6th stage ： With TRWKRNo rain on the day and the previous day
7th -17th stage ： No TRWKRNo rain on the day and the previous day

From Sanage
Brdg to Johoku Brdg
猿投橋～城北橋

100

Not enough data

Improved

80

Measures for water quality
improvement seemed to work.

60

decrease
40

32
21

20
0

36

H19.4.22～6.30

19

H20.4.1
～6.30

31
22

20

13

11
H21.4.1～6.30

H22.4.1～6.30

H23.4.1～6.30

H24.4.1～6.30

H25.4.1～6.30

H26.4.1～6.30

H27.4.1
～6.30

第1ｓｔ.
第1st.
第3st.
第5st.
第7st.
第9st. 第11ｓｔ.
第11st. 第13ｓｔ.第15ｓｔ.第17ｓｔ.
第13st.
第15st.
第17st.
第3ｓｔ.
第5ｓｔ.
第7ｓｔ.
第9ｓｔ.
27
25
20
22
42
16
9*
16

泡の発生状況_泡が川底から浮いてくる割合(%)

Number of33
data

Bubblesreported(%)

城北橋～朝日橋
From Johoku
Brdg to Asahi Brdg

100

Not enough data

80
60

40

40

21
20
0

8
H19.4.22～6.30

0H20.4.1～6.30

8
H21.4.1
～6.30

第1st.
第3st.
第5st.
第3ｓｔ.
第5ｓｔ.
Number of 第1ｓｔ.
data
12
12
14

20

10
0
H22.4.1～6.30

0H23.4.1～6.30

H24.4.1～6.30

H25.4.1～6.30

H26.4.1～6.30

H27.4.1
～6.30

第7st.
第9st.
第11st. 第13ｓｔ.
第13st. 第15ｓｔ.
第15st.
第17st.
第7ｓｔ.
第9ｓｔ.
第11ｓｔ.
第17ｓｔ.

5*

10

14

7*

5*

5*

Bubblesreported(%)

朝日橋～松重橋
From Asahi
Brdg to Matsushige Brdg

100
80
60

58

58

56
42

40

0

Improved
decreased

40

38

31
18

20

H19.4.22～6.30

H20.4.1～6.30

H21.4.1
～6.30

第1st.
第3st.
第5st.
第3ｓｔ.
第5ｓｔ.
Number of 第1ｓｔ.
data
45
81
31

泡の発生状況_泡が川底から浮いてくる割合(%)

泡の発生状況_泡が川底から浮いてくる割合(%)

Bubblesreported(%)

泡の発生状況_泡が川底から浮いてくる割合(%)

Bubbles from River Bottom from spring to early summer

Bubblesreported(%)

H22.4.1～6.30

H23.4.1～6.30

H24.4.1～6.30

H25.4.1～6.30

H26.4.1～6.30

24

H27.4.1
～6.30

第7st.
第9st. 第11ｓｔ.
第11st. 第13ｓｔ.
第13st. 第15ｓｔ.
第15st. 第17ｓｔ.
第17st.
第7ｓｔ.
第9ｓｔ.
24
39
19
35
29
32

松重橋～大瀬子橋
From Matsushige
Brdg to Oseko Brdg

100
80
60
40
20
0

Number ofdata

Improved
7
H19.4.22
～6.30

14
3
H20.4.1
～6.30

13

0
H21.4.1～6.30

H22.4.1～6.30

H23.4.1～6.30

decreased

875

H24.4.1～6.30

H25.4.1～6.30

H26.4.1～6.30

0H27.4.1～6.30

第17ｓｔ.
第1st.
第3st.
第5st.
第7st.
第9st.
第11st. 第13ｓｔ.
第13st. 第15ｓｔ.
第15st.
第17st.
第1ｓｔ.
第5ｓｔ.
第11ｓｔ.
第3ｓｔ.
第7ｓｔ.
第9ｓｔ.
27
28
24
30
25
29
19
15
15

Bubbles from River Bottom from spring to early summer improved from Sanage Brdg to Johoku Brdg and from Asahi Brdg to
Ohseko Brdg. State of river bottom bubbles may easily be effected by temperature or tide, but recent measures for water quality
improvement worked. We need to continue the survey to make it clear.

55

1st -6th stage ： With TRWKRNo rain on the day and the previous day
7th -17th stage ： No TRWKRNo rain on the day and the previous day

猿投橋～城北橋
From Sanage
Brdg to Johoku Brdg

*lesser data number

100

High temperature worsened
the condition,.

80
60
40
20
0

25
6
H19.9.8～12.160
H20.9.28～12.16

6
H21.9.27～12.1613
H22.9.11～12.17

13
H23.9.11～12.1617
6

H24.9.22～12.16

H25.9.29～12.17

H26.9.29～12.1613
H27.9.20～12.16

第2st.
第4st.
第6st.
第8st.
第10st.
第12st.
第14st.
第16st.
第18st.
Number of 第2ｓｔ. 第4ｓｔ. 第6ｓｔ. 第8ｓｔ. 第10ｓｔ. 第12ｓｔ. 第14ｓｔ. 第16ｓｔ. 第18ｓｔ.
23
12
data
15
9*
17
47
17
16
20

泡の発生状況_泡が川底から浮いてくる割合(%)

Bubblesreported(%)

城北橋～朝日橋
From Johoku
Brdg to Asahi Brdg

100*lesser data number

80
60

High temperature worsened
the condition,.

40

17

20

5
0

H19.9.8～12.1600

00

H20.9.28～12.16

H21.9.27～12.16

H22.9.11～12.17

H23.9.11～12.16

H24.9.22～12.1617
0

0H25.9.29～12.17

H26.9.29～12.16

H27.9.20～12.16

Number of
第2st.
第4st.
第6st.
第8st. 第10ｓｔ.
第10st. 第12ｓｔ.
第12st. 第14ｓｔ.
第14st. 第16ｓｔ.
第16st. 第18ｓｔ.
第18st.
第6ｓｔ.
第8ｓｔ.
第2ｓｔ.
第4ｓｔ.
data

21

2*

3*

5*

12

12

10

6*

6*

泡の発生状況_泡が川底から浮いてくる割合(%)

Bubblesreported(%)

Bubblesreported(%)

朝日橋～松重橋
From Asahi
Brdg to Matsushige Brdg

100
80High temperature worsened
the condition,.

60
40

23

35

30
13

20
0

19

12

0
H19.9.8～12.16

H20.9.28～12.16

H21.9.27～12.160
H22.9.11～12.17

H23.9.11～12.16

H24.9.22～12.16

H25.9.29～12.17

7
H26.9.29～12.16

H27.9.20～12.16

Number of 第2ｓｔ.
第6ｓｔ.
第2st.
第4st.
第6st.
第8st. 第10ｓｔ.
第10st. 第12ｓｔ.
第12st. 第14ｓｔ.
第14st. 第16ｓｔ.
第16st. 第18ｓｔ.
第18st.
第8ｓｔ.
第4ｓｔ.
data

104

Bubblesreported(%)

泡の発生状況_泡が川底から浮いてくる割合(%)

泡の発生状況_泡が川底から浮いてくる割合(%)

Bubbles from River Bottom from Autumn to early Winter

27

15

23

42

40

24

29

31

松重橋～大瀬子橋
From Matsushige
Brdg to Oseko Brdg

100
80
60
40

Increased

2030

H19.9.8～12.16000H20.9.28～12.16

H21.9.27～12.16

H22.9.11～12.17

3
H23.9.11～12.16000H24.9.22～12.16

H25.9.29～12.17

H26.9.29～12.16

5
H27.9.20～12.16

第2st. 第4ｓｔ.
第4st. 第6ｓｔ.
第6st.
第8st. 第10ｓｔ.
第10st. 第12ｓｔ.
第12st. 第14ｓｔ.
第14st. 第16ｓｔ.
第16st. 第18ｓｔ.
第18st.
第8ｓｔ.
Number of 第2ｓｔ.
data
34
19
12
20
9*
24
31
24
22

State of bubbles got worse compared 8th stage to 18th stage between Johoku brdg and Oseko
brdg. High temperature appears to cause it.

56

Ｓｔａｔｅ ｏｆ Ｂｕｂｂｌｅｓ ｉｎ ａｌｌ ｓｅｃｔｉｏｎｓ
Asahi brdg

1st -18th stage ;including all condition

Tidal flow reaches
around Nayabashi brdg
and Habashita brdg, it
makes froating sludge
gathered.

Frequencyof100
bubble occurrencedays(%)

川底からのあわ 構成比(%)

90
80
70

Habashita brg

Kitashimizu
Hydrophilic Square

Nishiki brdg

River widens and flows
slowly near Kitashimizu
hydrophilic square, so
sludge easily heaps.

60
50
40
30
20

Naya brdg

Johoku brdg -Sanage brdg

Matsusige brdg – Asahi brdg

Asahi brdg – Johoku brdg

0

港新橋*
きらく橋
紀左ヱ門橋
大瀬子橋
白鳥橋
御陵橋
熱田記念橋
旗屋橋
瓶屋橋
住吉橋
尾頭橋
古渡橋*
山王橋
松重橋
日置橋
岩井橋
洲崎橋*
新洲崎橋
天王崎橋
納屋橋
錦橋
伝馬橋
桜橋*
中橋*
五条橋
景雲橋
小塩橋
巾下橋
朝日橋
大幸橋*
鷹匠橋*
筋違橋
堀端橋*
中土戸橋
城北橋
金城橋
田幡橋*
北清水橋
黒川橋*
志賀橋
猿投橋
稚児宮人…
木津根橋
瑠璃光橋*
辻栄橋*
黒川1号*
夫婦橋
旭橋*
栄橋*

10

* 10 and under data number

At survey of river bottom near
Kitashimizu brdg On December 26th , thebottom could be seen Cleary(not sodark)from top of bridge, and bubbles
were not seen.

Many bubbles

Many bubbles

Secretariat thinks that measures forwater quality improvement worked,
and bubbles from river bottom
decreased.

River bottom under Kitashimizu bridge
photo by secretariat; 12/26/2015

57

６.６. Ｓｍｅｌｌ
The ratio of “Terrible smell – smell ” was 44%, when “bubbles
from the bottom”. On the other hand, That was 19 %, when “nobubbles from the bottom”.
Smell often worsened, when “bubble from the bottom” appeared.
This tendency is clear between Asahi Bridge and Matsushige
Bridge compared to other areas in 15th stage.

The difference in the occurrence of smell
between “bubbles from the bottom” and“no bubbles from the bottom”.
All stage, with TRWKR and No TRWKR including all surveys
No rain on the day and the previous day

Sanage Bridge～Minatoshin Bridge

Relation between “bubbles” and “smell”

The total rate of terrible smell.
Bad smell and smell is 44％

Asahi Bridge ～ Matsushige Bridge
Between Asahi Bridge – Matsushige Bridge
Average of each stage
1st – 6th stage ： with TRWKRNo rain on the day and the previous day
7th – 16th stage ： with TRWKRNo rain on the day and the previous day

The total rate of terrible smell.
Bad smell and smell is 17％

Bubbles; percentage of that from the bottom of the river59

Change in occurrence of smell（Average in some section）

1st – 6th stage ： With TRWKRNo rain on the day and the previous day
7th – 18th stage ： With TRWKRNo rain on the day and the previous day* Except the data between Minatoshin Bridge and Oseko Bridge.

With TRWKR

Form of pool and shoal
Utilization of groundwater
Increase of raw water transmission from Shonai River
Covered sandIntroduction of advanced water treatment at Meijo Water Treatment Center
In-service of Horikawa Ugan Rain-water Reservoir for pollution control
Utilization of reclaimed wastewater at Moriyama Water Treatmenｔ Center(Section)
Sakae Bridge～Sanage Bridge

％
9

3

7

50

0

0

0

13

0

0

0

0

0

0

0

0

0

0

27

2

15

9

10

6

29

6

10

17

16

25

6

0

0

0

22

7

（not enough data）

Sanage Bridge～Johoku Bridge
Johoku Bridge～Asahi Bridge

After the stop TRWKR
Improved / kept
50

Matsushige Bridge～Oseko Bridge

0

50

16

0

With TRWKR→Improved / kept

（not enouh data）

Asahi Bridge～Matsushige Bridge

15

40

33

0

7

41

14

36

20

0

0

0

After the stop TRWKR→Worsened

4

43

19

44

12

32

9

19

26

35

8

39

10

17

15

39

11

31

4

46

15

38

29

4

38

54

13

15

0

20

14

3st.

4st.

5st.

6st.

7st.

8st.

9st.

23

37

7

12

1st.

2st.

39

60

%

10st. 11st. 12st. 13st. 14st. 15st. 16st. 17st. 18st.
%“Occurrence of smell” improved and kept after the stop TRWKR. It is considered that measures forwater quality improvement seemed to work .

60

Upstream
SectionOccurrence of Smell(Average from Sakae Bridge to Sanage Bridge)
With TRWKR

1st – 6th stage ： With TRWKRNo rain on the day and the previous day
7th – 18th stage ： With TRWKRNo rain on the day and the previous day

Form of pool and shoal
Utilization of groundwater
Increase of raw water transmission from Shonai River
Covered sandIntroduction of advanced water treatment at Meijo Water Treatment Center
In-service of Horikawa Ugan Rain-water Reservoir for pollution control
Utilization of reclaimed wastewater at Moriyama Water Treatmenｔ Center

There is no reports of “Terrible smell – smell”
after 9th stage, in Upstream section

Sample23*Few data

40

15

2*

8*

3*

5*

8*

5*

9*

9*

8*

8*

7*

7*

1*

4*

4*

■ Change of smell in upstream section→ There is no reports of “terrible smell - smell” , after 9th stage, although few data.

61

Occurrence of Smell

Middle andDownstream Section（Average from Sanage Bridge to Oseko Bridge）

With TRWKR

1st – 6th stage ： With TRWKRNo rain on the day and the previous day
7th – 18th stage ： With TRWKRNo rain on the day and the previous day

Form of pool and shoal
Utilization of groundwater
Increase of raw water transmission from Shonai River
Covered sandIntroduction of advanced water treatment at Meijo Water Treatment Center
In-service of Horikawa Ugan Rain-water Reservoir for pollution control
Utilization of reclaimed wastewater at Moriyama Water Treatmenｔ Center

High temperature worsened the condition, whichcaused blue tide and red tide coming upstream,and sludge floated on the surface of the river.

With TRWKR
Improved/kept

With TRWKR
Improved/kept
Worsened

Sample

106

210

170

50

109

62

84

67

75

113

108

98

93

82

87

62

74

82

■ Change of smell in middle stream and downstream section
After the TRWKR, the smell was worsened. After that, at 12th and 13th stage, the smell
worsened, but in other stages, it improved.

62

1st, 3rd, 5th stage ：With TRWKRNo rain on the day and the previous day
7th, 9th, 11th, 13th, 15th, 17th stage：No TRWKRNo rain on the day and the previous day

Occurrence of smell
Spring～Early summer
Improved＊Few data→It’s assumed that there
are results obtain by newwater quality improvement
measureDecreased

Sample

33

42

30

24

20

25

16

16

9*

Decreased

Sample 46

81

37

25

22

43

35

34

29

High temperature worsened the condition, whichcaused blue tide and red tide coming upstream,and sludge floated on the surface of the river.
＊Few data

Sample

12

14

13

5*

9*

14

7*

5*

Decreased

6*

Sample

15

33

29

30

24

26

Occurrence of smell from spring to early summer was improved between Sanage Bridge and Oseko Bridge After the stop
TRWKR. Because Occurrence of smell is easily affected by temperature and observed time tidal, some points can not be
confirmed. Although it’s assumed that there are results of new water quality measure. We need to continue the survey tomake it clear.

35

32

30

63

2nd, 4th, 6th stage： With TRWKRNo rain on the day and the previous day
8th ,10th ,12th ,14th ,16th , 18th stage ： No TRWKRNo rain on the day and the previous day

Occurrence of smell
Autumn～Early winterHigh temperature worsened the condition, whichcaused blue tide and red tide coming upstream,and sludge floated on the surface of the river.

Sample

47

11

17

16

23

20

17

11

15

High temperature worsened the condition, whichcaused blue tide and red tide coming upstream,and sludge floated on the surface of the river.

Sample107

High temperature worsened the condition, whichcaused blue tide and red tide coming upstream,and sludge floated on the surface of the river.

28

16

25

43

40

25

29

32

High temperature worsened the condition, whichcaused blue tide and red tide coming upstream,and sludge floated on the surface of the river.

not enough data
not enough data

Sample

21

2*

4*

5*

12

12

11

6*

7*

Sample35

9*25

Occurrence of smell at 18th stage was almost the same as that at 17th stage after thestop TRWKR.

21

35

26

29

16

28

64

1st ,3rd ,5th stage
With TRWKRNo rain on the day andthe previous day

Kind of smell（each division）・・・spring～early summer
With TRWKR

7th, 9th, 11th, 13th, 15th, 17th stage
No TRWKR
No rain on the day andthe previous day*Few data

No data

*

*

86%

82%

*

*

*

*

*

■ Change of the smell, fromspring to early summer, between
Sanage bridge to Minatoshin
Bridge→The ratio of “Ditch” and“Sludge” was about 80%. Each
was about 40%.
There is no significant change in
7th stage and 17th stage

With TRWKR
79%

88%

76%

86%

86%

8１%

About 40%

No data

The rate of “Ditch”＋“Sludge” is about 80%

About 40%
* 0％ item isn’t displayed.

65

2nd, 4th, 6th stage
With TRWKRNo rain on the day andthe previous day
8th ,10th ,12th ,14th ,16th , 18th stage
No TRWKR
No rain on the day andthe previous day

Kind of smell（each division）・・・autumn～early winterWith TRWKR

Not enough data

*

*

*

*

*

83%

83%

*

*

*

*

■ Change of the smell, fromautumn to early winter, between
Sanage bridge to Minatoshin
Bridge→The ratio of “Ditch” and“sludge” was about 70%.
In 18th stage, it was especiallyreduced the smell of “Ditch”
and “Sludge” than in 8th stage.

With TRWKR
95%
81%

70%

86%
80%
68%

Decreased

Decreased
The rate of “Ditch”＋“Sludge” is about 70%* 0％ item isn’t displayed

66

６.７. Colors①colorless⑥gray⑪dark gray②milky white⑦yellow gray

⑫pale gray yellow③yellow⑧pale gray yellow green⑬yellow brown④yellow green⑨gray yellow green⑭brown⑤greeen⑩gray green⑮green brown⑤green⑦yellow gray＊photos
Shiratori Bridge…pale gray yellow
photos: secretariat , November 11 2015

⑧pale grayyellow green⑨gray yellow
green

Legend■red tide■milky⑬yellow brown②milky white⑭brown⑧pale gray
⑮green brownyellow green⑫pale yellow gray■sludge⑥gray⑩gray green⑪dark gray

⑩gray green

We classify thecolors into threegroups, milky, redtide, sludge on thebasis of the data of
the Fixed Point
Observation.

⑪dark gray

These photos were taken on
November 11, 2015 around
Shiratori Bridge. The color of theriver was pale gray yellow.
There were many labored mullets
at the surface of the river.
There was a smell of the rotten
egg odor(hydrogen sulfide).

71

Ratio of color

2nd-6th stage ： With TRWKRNo rain on the day and the previous day

Sanege Bridge ～ Minatoshin Bridge

Frequent colors：⑧pale gray yellow green, ⑨gray yellow green, ⑩gray green
7th stage

8th stage

9th stage

10th stage

11th stage

12th stage

13th stage

14th stage

15th stage

16th stage

17th stage

18th stage

20

19
18
17
16
15
1213 12
11
1010

17

19

19

6
5

⑨gray
yellow green

1

13
13
12
10

⑧pale grayyellow green

2 2 23
1 1⑦yellowgray

0

1③yellow

5
4 3
3
2 2
1 1

②milky
white

6 6
5

⑥gray

10 9

⑤greeen

10

14
12 12
11
10
10
9
9
7
6
6 6
6 6
5 4 6
5 5 5 5
5 4
3
3
32
3
3
3
33
2 2 222 3
2
1 12
1 1 1 1 1 1 01 1 1 1 1④yellowgreen

15①colorless

Ratio of kind of color(%)

25

Number of research
2nd stage 213 11th stage 113
3rd stage 176 12th stage 98
4th stage 52
13th stage 93
5th stage 111 14th stage 82
6th stage 63
15th stage 89
7th stage 85
16th stage 63
8th stage 67
17th stage 77
9th stage 76
18th stage 90

39

37
35
34
33 34 33
32 32
31
31
30
30 30
27
27
25
24 24
24 24
22
22
21
20
20

35
30

41

41

3

13
9

99

88
67 7
6
65
6
4
4
5 5 4
5
4
44
3
3 3 3 34 3 4
4
3
3
2 2
3 2 22
2 22
2
22
2
2
1
2
1
1
1 11
11
1 11
0
0

1

0

⑯the others

6th stage⑮greenbrown

5th stage⑭brown

4th stage⑬yellowbrown

3rd stage⑫pale grayyellow

40

2nd stage⑪dark gray

45

⑩gray green

50

57th-18th stage ： No TRWKR No rain on the
day and the previous day■Frequent colors?
⑧pale gray yellow green,⑨gray yellow green,⑩gray green

72Change of colors(spring ～ early summer)

The 7th, 9th, 11th, 13th, 15th 17th stage:
No TRWKR ,No rain on the day and the previous day

Legend■ red tide
■ milky⑬yellow brown②milky white⑭brown⑧pale gray
⑮green brownyellow green⑫pale yellow gray■ sludge⑥gray⑩gray green⑪dark gray( ) the number of survey

increased

Note: ※ few data

decreased■ Change of colors after the stopof TRWKR→The ratio of Milky increased, redtide decreased, colorless increased
compared with 7th stage.
In the 17th stage, compared to the15th , the ratio of milky and sludge
increased, the ratio of red tide
decreased.
We think that the water quality has
get better by the new measures forwater quality improvement. We needto ascertain the facts by continuous
survey.

increased

Ratio of Milky increased→red tide decreased, colorless increased73

Ratio of color (spring ～ early summer)

decreased

decreased increased

Ratio of Milky, sludge decreased→colorless increased( ) the number of survey

The 7th, 9th, 11th, 13th, 15th 17th stage:
No TRWKR ,No rain on the day and the previous day

decreased
increased
increased
Ratio of Milky, sludge increased→red tide decreased( ) the number of survey

decreased
Note: ※ few data

increased
Sludge increased■ Change of colors after the stop of TRWKR
Ratio of Milky, sludge decreased, and colorless increased after the stop of TRWKR at 17th stage around Sanage Bridge～Johoku Bridge.
Ratio of Milky, sludge increased, red tide decreased around Asahi Bridge ～ Oseko Bridge. We think that colorless increased Sanage Bridge～Johoku Bridge by the new measures for water quality improvement. We need to ascertain the facts by continuous survey.

74

Change of colors(Autumn ～ Early Winter)

The 8th, 10th, 12th, 14th, 16th 18th stage:
No TRWKR ,No rain on the day and the previous day

Legend■ red tide
■ milky⑬yellow brown②milky white⑭brown⑧pale gray
⑮green brownyellow green⑫pale yellow gray■ sludge⑥gray⑩gray green⑪dark gray( ) the number of survey

Note: ※ few data

■ Change of colors after the stopof TRWKR→Sludge increased, Milky and red
tide decreased, colorless increased
compared with 7th stage.
We think that colorless increased
at 16th and 18th stage by the newmeasures for water quality
improvement. We need to ascertain
the facts by continuous survey.

increased
decreased

decreased
increased
Sludge increased→Milky and red tide decreased、colorless increased75

Ratio of color (Autumn ～ Early Winter)decreased( ) the number of survey
Note: ※ few data

increased increased

Sludge increased→Milky decreased、colorless increased

decreased

The 8th, 10th, 12th, 14th, 16th 18th stage:
No TRWKR ,No rain on the day and the previous day

increased

decreased( ) the number of survey

Sludge increased→Milky and red tide decreased

decreased
Red tide decreased■ Change of colors after the stop of TRWKR
Sludge increased, and milky decreased、colorless increased at 17th stage around Sanage Bridge～Johoku Bridge compared with the stage after thestop of TRWKR. Milky and red tide decreased around Asahi bridge and Oseko bridge. We think that colorless increased at 16th and 18th stage
around Sanage Bridge～Johoku Bridge by the new measures for water quality improvement. We need to ascertain the facts by continuous survey.

76

６.８. Litters
Litters
Change in Frequency of finding Litters on Riverside Ways
（From 2nd to 18th stage, all section）

Frequency ofLitters weredecreased
to about 30%“PE shopping bag 1.8”means that PE
shopping bag was found 1.8 times in 10
investigations. (or 18 times in100
investigations)

From 2nd to 6th stage ：With TRWKR No rain on the day and the previous day
From 7th to 18th stage ：No TRWKR No rain on the day and the previous day■Litters component：Plastic wastes(PE, plastic bag, noodle cup, foam tray,
pet bottle ,etc.), can, glass, cigarette (wrapping, butt)

Litters collected in the clean-up activities in 2nd stage（Photo： October 25, 2008）

Total of 18 kind of
Frequency of finding
Litters every stage

Note: Frequency (times/10 investigations)＝ thetimes of finding/the times of investigations*10＊ Frequency is not the amount of Litters.
If we found a kind of Litter, we counted one finding.

■Frequency of finding Litters on Riverside Ways?
Frequency of Litters in 18th stage were decreased to about 30%(8.1/26.0*100=31%) as compared to 2nd stage
starting investigations. This is the result that we can feel a change in the consciousness of citizens have appeared byspreading the relation of citizen loving Horikawa rever, and increasing the organizations and the companies cleaning
Horikawa rever.
Cigarette butt was the most frequency Litters.

77

Litters on Riverside Ways

With TRWKR（From 2nd to 18th stage, each section）

From 2nd to 6th stage ：With TRWKR No rain on the day and the previous day
From 7th to 18th stage ：No TRWKR No rain on the day and the previous day■Litters component：
Plastic wastes(PE, plastic
bag, noodle cup, foam
tray, pet bottle ,etc.),can, glass, cigarette(wrapping, butt)

Plastics : in decreasing trend

Lots of butt
Note: Component ratio(%)＝the number of sighting each kind of litter／the number of sighting all kind oflitter ×100
Litter does not include leaves, branches and grass.
＊The number of sighting is not the number of litters.
We count one, even if at least one litter is sighted in the survey.
■What kind of litters was found on the riverside ways more frequently?
→ The rate of cigarette was high. Plastics are in decreasing trend.

Conspicuous littering ofcigarette butts.

78

From 2nd to 6th stage ：With TRWKR No rain on the day and theprevious day

Change in Floating Litters

From 7th to 18th stage ：No TRWKR No rain on the day and theprevious day■Litters component：Plastic wastes(PE, plastic bag, noodle cup, foam tray,
pet bottle ,etc.),can, glass, cigarette (wrapping, butt)

Number of survey
1st stage：145
2nd stage：255
3rd stage：191
4th stage：54
The floating litters were
5th stage：119
decreased to less than 50%
6th stage：66
7th stage：90
Decreased to 1.4
8th stage：75
per one survey
9th stage：81
10th stage：122
Rate of11th stage：122
plastics is high 12thstage：106
13th stage：101
14th stage：89
15th stage：96
16th stage：64
17th stage：81
18th stage：94■What trend the floating litters go?→The
number of floating litters at 18th stage was
1.4litters/one survey. The floating litterswere decreased to less than 50% ascompared to 1st stage.
Rate of plastics was high, and the numberof plastic was 0.9 per one survey.

Cleaning
ship
The sum of each stage,
The number of litters per
one survey

Note: the number of litters per one survey ＝ the number of each littersfound in all survey / the number of surveys＊the number of litters is the number of litters found in all survey
If the number of litters was reported “countless（=***）”in some survey,
it count ”10”, the maximum number of other reports.

79

From 2nd to 6th stage ：With TRWKR No rain on the day and the previous day
From 7th to 18th stage ：No TRWKR No rain on the day and the previous day

Change of the number of Floating Litters

Downstream
A small number ofdata

Number of survey
1st stage：32
2nd stage：42
3rd stage：15
4th stage：2
5th stage：8
6th stage：3
7th stage：5
8th stage：8
9th stage：5

10th stage：9
11th stage：9
12th stage：8
13th stage：8
14th stage：7
15th stage：7
16th stage：1
17th stage：4
18th stage：4

Litters Catcher Johoku Bridge（Photo： by secretariat, December 26, 2015）

Floating litters in “Sanage Bridge ～ Johoku Bridge” section decreased in 17th and 18th stage.

Decrease

Number of survey
1st stage：37
10th stage：23
2nd stage：47 11th stage：27
3rd stage：42
１2th stage：20
4th stage：11
13th stage：16
5th stage：30
14th stage：17
6th stage：17
15th stage：16
7th stage：24
16th stage：12
8th stage：16
17th stage：12
9th stage：20
18th stage：20

Captured litters are pulled up
on a regular basis, it isdisposed of is recovered.

Litters collection
basketLitters collection
basketFloating
Litters
To

Inflow gate

Down
streamCollection fence

UpperstreamBy utilizing the low tide, Littersgather in one place collecting fence.
Installation condition of the facility

A small number of Number of survey
10th stage：12
data
1st stage：12
2nd stage：21
3rd stage：14
4th stage：2
5th stage：13
6th stage：4
7th stage：6
8th stage：5
9th stage：9

11th stage：14
12th stage：12
13th stage：7
14th stage：11
15th stage：5
16th stage：6
17th stage：6
18th stage：8

Weir

wa
te
r
tr
ea
tm
en
t
ce
nt
er

Caught litters arecaptured in the litterscollection basket.

In
flow
gate

SewageHorikawa
river

Depending on the water level ofrever, inflow gate falls in the② Horikawa
automatic, then foating litters are catched.

Sectional view (image)Document： Website of Nagoya city
http://www.city.nagoya.jp/ryokuseidoboku/page/0000009101.html■What trend floating litters in Sakae Bridge ～ Asahi
Bridge go?
→Floating litters in “Sanage Bridge ～ Johoku Bridge”
section decreased significantly in 17th and 18th stage.
As a factor, it is considered that of the two.
①Litters to fall on the river like the wind decreased,because litters on riverside way decreased by a change inthe consciousness of citizens.
②Floating litters are effectively removed, so litterscatcher established in downstream of Johoku Bridge isoperated well.

80

Change of the number of Floating Litters

In decreasing trend

調査回数
第１ stage：46
第2 stage：107
第3 stage：82
第4 stage：28
第5 stage：37
第6 stage：16
第７ stage：25
第8 stage：25
第9 stage：22

From 2nd to 6th stage ：With TRWKR No rain on the day and the previous day
From 7th to 18th stage ：No TRWKR No rain on the day and the previous day

第10 stage：43
第11 stage：43
第12 stage：40
第13 stage：35
第14 stage：25
第15 stage：34
第16 stage：29
第17 stage：29
第18 stage：32

photo:by secretariat

Floating litters in “Sanage Bridge ～ Johoku Bridge” section decreased mostly plastic.
In decreasingtrend

A small number of
data

調査回数
第１ stage：15
第2 stage：36
第3 stage：33
第4 stage：9
第5 stage：29
第6 stage：25
第７ stage：30
第8 stage：21
第9 stage：25

Kameya Bridge～Sumiyoshi Bridge
By having been removed the raft in thewater’s edge, it decreased thefrequency to see the litters.

第10 stage：35
第11 stage：27
第12 stage：26
第13 stage：35
第14 stage：29
第15 stage：34
第16 stage：16
第17 stage：30
第18 stage：30

調査回数
第１ stage：3
第2 stage：2
第3 stage：5
第4 stage：2
第5 stage：2
第6 stage：1
第7 stage：0
第8 stage：0
第9 stage：0

第10 stage：0
第11 stage：0
第12 stage：2
第13 stage：0
第14 stage：0
第15 stage：0
第16 stage：0
第17 stage：0
第18 stage：0■What trend floating litters in Asahi Bridge ～Minatoshin Bridge go?
→Floating litters in “Sanage Bridge ～ Johoku
Bridge” section decreased mostly plastic.
As a factor, it is considered that of the two.
①Litters to fall on the river like the wind decreased,because litters on riverside way decreased.
②By having been removed the raft in the water’sedge in Kameya Bridge～Sumiyoshi Bridge, litters
are no longer stagnant.

81

Kind of floating Litters（component ratio）

With TRWKR■Litters component：Plastic wastes(PE, plastic bag, noodle cup, foam tray,
pet bottle ,etc.), can, glass, cigarette (wrapping, butt)

From 2nd to 6th stage ：With TRWKR No rain on the day and the previous day
From 7th to 18th stage ：No TRWKR No rain on the day and the previous day

Rate of plastics is highNote: Rate of litters(%)＝the number of each kind of litters ／the number of all kind litters×100
the number does not include leaves branches and grass＊the number of litters was found through all surveys“if some kind of litters were found ”countless (=***)”in some survey, it counts “10”,the maximum number in one ubstituted for the number of “countless”.
■What kind of floating litters were found frequently?
→The rate of plastics is high, about 60%(18th stage), in decreasing trend.

82

６.９. Living things
Horikawa was polluted in rapid-economic growth period, so
called “dead river”. But now, various living things can beseen, for example Kingfisher, although the river flow
through the center of Nagoya city.
錦橋でネイチャーウォッチング
Sep.18 2015(Fri.) Report・Photo: Kawasemi-chosatai

白鳥付近 たくさんのボラが水面付近で苦しそうにしている様子
モクズガニも水面付近に避難Nov. 11 2015（Wed.） Report・Photo：Kawasemi-Chosatai

カワセミ

イソヒヨドリ

ハクセキレイスッポン

ミシシッピアカミミガメ
（外来種）

ギンヤンマ
（産卵中）

Nakatsuchido Bridge Living things Observation Diary
Report・Photo：Sato family Chosatai
Sep.15 2015（Tue.）
カメが甲羅干しカルガモ８羽上流へ。
対岸の葦に小さなアオサギ。

熱田記念橋 カラスの大軍と鴨の群れ
Dec. 25 2015（Fri.） Report・Photo：Chikyukurabu-Chosatai

私どもは、川魚が定着すれば、先ず生きた川に発展すると考えました。そのために中土戸橋周辺の川が何を望んでいるかを、歩いて知ろうと考えました。特別テーマは別にして、間口を大きくしないた
めにも１日をA4で纏めることにしました。そして１年２００回を目標としています。
Nov. 29 2015（Sun.）
水鳥の数が増える。星羽白の数が多い。
カルガモ、カワウ、セキレイ、白鷺、鵜。小鴨が約100羽。
中土戸橋下流に金黒羽白約60羽、筋違橋に約２０羽。
お堀に星羽白と金黒羽白の場所にユリカモメが約４０羽。
中土戸橋でタヌキに遭遇 !?
Jan. 27 2015

Oct. 9 2015（Fri.）
鵜が小魚をくわえて出る。
カワセミが葦の根本近くにとまる。
タヌキの糞見当たらず。

（資料）第16回調査隊会議 p.80
Dec. 10 2015（Thu.）
小鴨と星羽白50羽程。金黒羽白の姿はなく、星羽白の数が少ない。
小鴨が6,7羽コンクリートの水垢を啄んでいる。カイツブリの姿は見えない。
下流に金黒羽白の二つのグループは健在で、お堀には金黒羽白と星羽白が戻っていた。ユリカモメは20羽以下に減少し、鵜の姿は見えず。狸の糞、認められず。

83

６.１０. Wind

Direction of windWind from the side

Wind to the upstream

The wind often blows
along the Horikawa riverWind to the downstream■Direction of wind
Data: all data of 1st stage to18th stage
The wind often blows along
the Horikawa river than fromthe side.
At Nishiki Bridge, the windblowed along the river about
80%.

84

６.１１. State of Shin-Horikawa River
Shin-Horikawa River

Impression of water pollution

Maizuru Bridge

All data included

Uzura Bridge

Impression of water pollution was worth between Maizuru Bridge and Oi Bridge.

94％

Horagai Bridge

94％

Tateishi Bridge
72％
62％

74％

60％

Hinode Bridge

Ukishima
Bridge**Atsuta Bridge** Few data

■ Impression of water pollution
At upstream of Shin-Horikawa river, between Maizuru Bridge and Oi
Bridge, the rate of “dirty” or “slightly dirty” was over 70%.
At downstream, the rate was 62%.
Impression of water pollution is especialｌy bad between Maizuru
Bridge and Oi Bridge.

85

Transparency of Shin-Horikawa River
Low transparency at Atsuta and Oi Bridge*

Transparency of Oi bridge in
upstream of Shin-Horikawa
river, was 53cm, that was
shorter than 70cm.
That of Atsuta Bridge indownstream, was 65cm,thatwas shorter than 70cm.
Both were acceptable range forcitizen.

＊acceptable range for citizen: over 70cm transparancy****few data

COD of Shin-Horikawa River
17～19mg/L between Horagai and Maizuru Bridge**

COD level between Maizuru andHoragai Bridge ,in upstream of
Shin-Horikawa river, was 1719mg/l, That of Atsuta Bridge, indownstream, was 14mg/l.
Upstream was more high level
COD than downstream.

**few data86

Bubbles of Shin-Horikawa River“Bubbles rising from the bottom of river”
were seen at Maizurum, Uzura, Kinen and Oi
Bridge.
Especially, that were seen high ratio at
Uzura Bridge 65%.
No bubbles were seen between Horagai andAtusta Bridge.

Many bubbles
were seen at
Uzura Bridge

*

*

*

*few data

Smell of Shin-Horikawa River82％

The ratio of terrible smell or bad smell,between Maizuru and Horagai Bridge, was
25-82%. That was high in upstream thanin downstream.

The ratio of “terrible smell” or “bad smell” was highbetween Maizuru and Horagai Bridge.

50％

45％
36％
25％

*

*

*

*few data87

Kind of Smell from Shin-Horikawa River・smell of sulfur■ Kind of smell

・smell of oil
・no smell

In Addition to smell of “Ditch”,
Smell of “Sludge” and “Rottenegg” was occurred at upstream of
Uzura Bridge, Kinen bridge and Oi
Bridge.

Smell of “Sludge” and“Rotten egg” was occurredat Uzura bridge, Kinen
Bridge and Oi Bridge.

*

*

*

■ Colors*

Colors of Shin-Horikawa River*few data

Green brown→Lighter colors were seen
about 40% at Maizuru Bridge
and Kinen Bridge. Colloidal
particulate sulfur might cause
these colors.
And darker green colors seen
Light yellow gray at Kinen Bridge and Oi Bridge,
Horagai Bridge, Atsuta Bridge.
The color were fromphytoplankton.

Light gray yellow green

*

*

*

*few data88Horikawa Clean Experiment with Chinese Water Spinach and SunPatiens
June 19th ～ October 7ｔｈ, 2015
By Ena Agricultural High School, Nagoya Horikawa Lions Cluband EspecMic Corporation
Place：near the pier of Naya Bridge

June 19th

Chinese Water Spinach
Floating island of bamboo

Chinese Water Spinach
Miniature floating island
June 19th

June 19th

Image of cleaned Horikawa

SunPatiens floating island（Repotex）

SunPatiens floating island（Bestman island）
The sand of witheredsunpatiens was muddy
and black as sludge.

August 10th （7th week）
Withered105

Horikawa Clean Experiment with Chinese Water Spinach and SunPatiens
June 19th ～ October 7ｔｈ, 2015
Place：near the pier of Naya Bridge
June 22ｔｈ（3days after experiment start）

July 22th （4th week）

August 17th （8th week）

September 15th （12th week）

June 29th (1st week)

July 27th （5th week）

August 24th （9th week）

September 24th （13th week）

July 6th (2nd week）

August 4th （6th week）

September 1st （10th week）

September 30th （14th week）

July 13th （3rd week）

August 10th （7th week）

September 7th （11th week）

October 7th （15th week）

106

Horikawa Clean Experiment with Chinese Water Spinach and SunPatiens
June 19th ～ October 7ｔｈ, 2015
Place：near the pier of Naya Bridge

Harvest Working （October 7th）

Insects, Birds, and Crustaceans

photos by Kawasemi survey group

Orthetrum albistlyum

Lycaenidae

DamseflyAnax parthenope

Japanese mitten crab

Sesarmops
intermedium

Speceis of
Crabs and Shrimp

Black-backed wagtail

Blue rock-thrush

Grey heron

Two years ago, the root of chinese water spinach became black,but it became white this time.

October 16th ,2013（※１） Bestman island（※２） Rebotex

October 7th, 2015

November 26th , 2015
At two floating islands(※1,※2） introduced in June 2015, many kinds of plants
sprout and grow up. These species are seen at a path between rice paddies.
This result is considered valuable for examining what kind of plants can grow up at
midstream of Horikawa.

107

Horikawa Clean Experiment with Chinese Water Spinach and SunPatiens （2015）
Term：June 19th ～ October 7th, 2015 （15weeks）① Chinese Water Spinach ：Grow up smoothly② SunPatiens：Withered (7th week)

Continuous observation of plant succession in two floating islands
Term：October 8th, 2015 ～ （Ongoing）

Plants seen at a path between rice paddies occur naturallyex.) Brassicaceae, Cyperaceae～Impression about the plants that grow up in the floating islands～
From Mr.Morimoto of Ena Agricultural High School
December 23rd ,2015

1. Observing plant succession and change of its ecology①Confirm plant succession by letting the floating islands lie②Confirm the role of vegetation in this ecosystem by observing thefloating islands with flourish plants and gathering insects and birds.

2. Proposed Horikawa Canola Field Project① Cultivate and observe canola flower② Confirm the possibility of canola field on water③ Confirm the possibility for extracting and using canola-seed-oil※canola Field project for reviving
farmland that was damaged from salt by
tsunamiThey aim for reconstruction of the affected areaof tsunami of Great East Japan Earthquake bycultivating Brassicaceae which is strong in damage
from salt in the paddy fields.

■Sale of edible canola-flower andYukina→Regeneration of food production andfarm management■canola-seed-oil→Invigorating local communities by
renewable energy

108

The Graduate School of Agriculture, Tohoku Univ.
http://www.nanohana-tohoku.com/

６.１５. Progress of Citizen’s Awareness
Activities of studies

第５回
堀川ラウンドテーブル 開催
堀川まちづくりの会
平成２７年７月３１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・ロマン黒川・北区役所

黒川親子水遊び
平成２７年８月１１日（火）堀川１０００人調査隊2010 第１７回調査隊会議
平成２７年９月５日（土) 報告：事務局

黒川親子体験教室
平成２７年８月１５日（土）黒川川遊び
平成２７年８月１９日（水）中日新聞
平成２７年９月６日（日）
朝刊記事より飯田小学校４年生 堀川水質調査勉強会
平成２７年９月１５日（火）109Activities of “Free Survey Groups” & “Cheering Groups”
御用水跡街園の清掃活動
新堀町 空手道場の子供達
平成２７年９月２４日（木）報告：御用水跡街園愛護会
調査隊

第１６回 秋の堀川一斉大そうじ
主催：クリーン堀川
平成２７年９月１２日（土）報告：御用水跡街園愛護会調査隊
事務局

堀川まちづくりの会パネル展
平成２７年１０月８日（木）報告：御用水跡街園愛護会調査隊
英文ＨＰの第17弾、第1８弾をアップ
ＷＢＰ堀川応援隊

読売新聞
平成２７年
１１月８日（日）朝刊より

第４回 鯱城・堀川清掃大作戦
主催：鯱城学園
平成２７年１１月７日（土）報告：御用水跡街園愛護会調査隊
事務局

中日新聞
平成２７年
１１月１０日
（火）朝刊
より

110

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

歴史散策 開催
平成２７年１１月１４日（土）主催：北区役所
報告：御用水跡街園愛護会調査隊

堀川まちづくり啓発運動「遊んで堀川に親しんで」
平成２７年１１月１５日（日）イオンモール熱田店
報告：御用水跡街園愛護会調査隊
名古屋市への寄付金制度に「堀川再生の寄附金」が追加
中日新聞
平成２７年１１月１０日（火）朝刊より

堀川まちづくりパネル展
地下鉄星が丘駅ロビ－にて
平成２７年１１月１１日（水）報告：御用水跡街園愛護会調査隊

堀川ギャラリー「ヘドロを除去して魚を呼ぼう」
鯱城・堀川と生活を考える会
近藤佑輔氏
平成２７年１０月２７日（火）～１１月１５日（日）

堀川の歴史街歩き
高年大学鯱城学園２６期地域学科生
平成２７年１１月１９日（木）清掃活動・定点観測
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
平成２７年１１月１９日（木）111

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

中日新聞
平成２７年１１月２０日（金）
朝刊より

中日新聞
平成２７年１１月２１日（土）朝刊より

活動レポート：伊勢湾流域圏
活動レポート：環境ボランティア
再生ネットワーク事務局
サークル「亀の子隊」

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：明電舎錦調査隊
平成27年4月～12月

西区・円頓寺商店街東側出口にあたる堀川・五条橋の橋詰に親水広場が完成
平成２７年１１月

信濃毎日新聞平成27年１２月２０日（日）
朝刊より

112

Events
第１１回堀川エコロボットコンテスト開催
平成２７年８月２３日（日）主催：名古屋堀川ライオンズクラブ
協賛：名古屋工業大学

名古屋環境デー
平成２７年９月１９日（土）報告：御用水跡街園愛護会調査隊
展示：堀川ライオンズクラブ
高年大学の皆さん

平成２７年８月８日（土）小学生向けロボット工作教室
を開催
中日新聞 平成２７年８月２４日（月） 朝刊より

ナヤマルシェの様子
平成２７年１０月１０日（土）報告：御用水跡街園愛護会調査隊
やっとかめ文化祭
堀川と御用水跡街園の歴史と文化を学ぶ
平成２７年１１月１０日（火）報告：御用水跡街園愛護会調査隊

読売新聞
平成２７年８月２４日（月）朝刊より「堀川ウォ－タ－マジックフェスティバル」
平成２７年１０月１０日（土）～１１月８日（日）開催
報告：御用水跡街園愛護会調査隊「つながろう木曽
応援ありがとうキャンペーン」

堀川河畔に生まれた
名古屋の近代医学の歩み「衛生の道」を歩こう！
「衛生のみち」歴史ウォーク２０１５
主催： ＮＰＯ法人
市民まちづくり風の会

報告：事務局113

Events
第９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開催
場所：長野県木曽町
企画・実施：木曽三川がつなぐ山とまちインターネットフォーラム実行委員会
掘川１０００人調査隊２０１０実行委員会 共催
特別協賛：アサヒビール株式会社 一般社団法人、中部地域づくり協会
平成２７年１１月２８日（土） 報告：事務局

114

事務局：中日新聞名古屋市民版 平成２７年１２月１日（火） 朝刊より

事務局：信濃毎日新聞 平成27年12月20日（日） 朝刊より115