Implementation by
Nagoya City
Measures to makeHorikawa River Limpid
Summary meeting for the 29th stage
Nagoya City
Greenification & PublicWorks Bureau River Plannning Div.
Waterworks and Sewerage Bureau Sewerage Plannning Div.
Environment Bureau Local environmental measures Div.

1

Implementation by
Nagoya city
Greenification &PublicWorks Bureau
2Initiatives for clarification ofHorikawa River-①Removal of Sludge-

3◆Removal of Sludge in Horikawa River

・Development of Bank Protection in River
management project → ・After Bank Protection Works, River bed
Excavation and removal of sludge are
implemented at the same time
⇒Development from downstream＋Habashita
BridgeKurokawa Area

Development in Gojo-Bridege Area(2018-)
Development of bank protection + Removal of sludge

Gojo-Bridge
Area

Nayabashi Area

Bank Protection Works
Hioki Bridge

Oto Bridge
SumiyoshiBridge【Explanatory notes】
River Bed Excavation
and Removal of Sludge

RiverConfluence

Bank Protection Work（completion）
Bank Protection Works（Under construction）

River Bed Excavation andRemoval of Sludge at the same time

Steelpipe
piles are：現在の断面
drivenup
to 20
metersunderground.

4◆Removal of Sludge in Horikawa River

Improvement work of Bank Protection

location

ＭＧ（Mashine Guidance）
MonitorWork Status
SannouBridge
Furuwatari
BridgeＧＮＳＳ

Trial implementation at a construction site in 2021

Carry out construction using 3D data by 3D survey（ICT construction）
Carry out short time andhigh precision and plane
3D survey by Acousitic
measuring device (narrowmulti-beam)

BeforeconstructionionComparison before and Ater
after contrution
construction

Noteshallow

T.P.

Near Upstream ofFuruwatari Bridge

Image diagram

It was changed from green to blue by improvement Bank
protection⇒High-precision Digging Completed!
deep5

Improvement work of Bank Protection No.1

◆Removal of Sludge in Horikawa River①【Hioki Bridge Waterfront Square】（Upstream of Hioki Bridge）

Scheduled to e completed
at the end of October

Early October 2021

Around January 2021

Future image

6

Improvement work of Bank Protection No.2
◆Removal of Sludge in Horikawa River②【Oto Bridge Hydrophile Square】（Downstream of Oto Bridge）

completed
Around May2020

The End of September 2021

Future image

7

Initiatives for clarification ofHorikawa River-②Developments ofShallows and Depths-8

◆Developments of Shallows and Depths
Setting wooden piles and ripraps generates variable stream on the river for
enforcing river s self-purification function and creating habitats with growth ofplants.

…fish spawning andplants’ seed ashore…change of stream
Development in 2016
（Downstream of Meoto Bridge）

9

Construction of Shallows and Depths
Construction in 2010
(Downstream of Meoto Bridge)

Before (2009)

After (2013)

Construction in 2012
(Downstream of Kurokawa No.2 Bridge)

Before (2011)

After (2013)

Construction in 2013
(Upstream of Kurokawa No.2 Bridge)

Construction in 2015
(Downstream of Ruriko Bridge)

Before (2012)

Before (2015)

After (2015)

After (2016)10

Construction of Shallows and Depths
Construction in 2016
(Downstream of Meoto Bridge)

Construction in 2018
(Downstream of Kizune Bridge)

Before (2016)

Before (2018)

After (2016)

After (2018)

Construction in 2020
(Downstream of Sinhori Bridge)
Photos of the follow-up
are on the next page.

Before (2020)
Some of the creatures seen in the upstream of Horikawa River

Mallard

Pale chubJapanesemitten crab

Little egret

After (2020)
Improvement
・Variety and amount offish have increased.
（pale chub etc.)
・Benthos have increased.
（shrimp etc.)
・Plants have grow up more.

11Construction of Shallows and Depths
Follow-up of the Shallows and Depths constructed in March 2021

September 2021

March 2021
MAP

Horikawa River

close-up

Shinhori Bridge
Construction site

Tsujiei Bridge
In this construction project, we utilizing fused stone which is recycled from incinerated ash of waste.

12Initiatives for clarification ofHorikawa River-③ Use of shallow groundwater -13

◆Use of shallow groundwater ①・Scheduled to be installed inMoriyama Ward in FY2021.
（★in the following map）③①★
⑨③②
Sanage Bridge④⑥⑤⑧ ⑦
Meijo Park

★ Asahi Bridge upstreamMar.2013②Uprsteam of Seko Bridge
0.01m3/s

Nov.2005

Tsujei Bridge
0.01m3/s④Kizune Bridge
0.01m3/s⑤Mar.2015

Mar.2018

Mar.2014.

Sanege Bridge
0.01m3/s⑥

Shiga Bridge
0.01m3/s⑦

Oct.2004.

⑧Mar.2008

Shimizu spring water
0.0005m3/s

Mar.2016

Scheduled to be installedin FY2021.

⑨

Kinjo Bridge
0.01m3/s

Mar.2021

Nagoya castle

Kurokawa First Bridge
0.01m3/s

Nakatsuchido Bridge
0.01m3/s※②③
The wells are broken.
⇒We are studying torepair

14

Initiatives for clarification ofHorikawa River-④Change of collected pollutants -15

■Removal of inflow of pollutants◆Garbage catcher（Near Johoku Bridge) since 2006

garbage basket

garbage basket
pollutants

Sanage Bridge
inflow gate
inflow gate

Installationlocation

capturing fence

The exterior Garbage catcher

Meijo Park

Cross Section

Nagoya Castle
Koshio Bridge
Naya Bridge

16

■ Removal of pollutants
２ Cleaning by NAGOYA Seiko-kai (Publicinterest incorporated association for cleaning
Nagoya Ports)

17

■Collection of pollutants
３

Change of collected pollutants
(ｔ)

単位：トン

Change of collected pollutants
ゴミ回収量推移NAGOYA
Seiko-kaiGarbagecatcher

20122013

2014

20152016

2017

2018

20192020※参考値value※temporary18

Initiatives for clarification ofShin-Horikawa River

19

■Survey and study for improvement of water
environment of the Shin-Horikawa River (2020)

For improvement the water environment of the Shin-Horikawa River,
we verified and evaluated the effectiveness of various water
purification measures in consideration of experts opinions, andformulated future purification policies.
List of experts
NameKenji Daito
Akihiro Tominaga

Belong toSpecialized field

Daido University

Professor

Environmental
Geotechnics,
Sedimentology

Nagoya Institute of Technology

Professor

River Engineering
Hydraulics

Naoki Matsuo

Chubu University

Professor emeritus

River Engineering
Environmental
Hydraulics

Akihiko Yagi

Aichi Institute of Technology

Visiting professor

Limnology

Naoko Yoshida

Nagoya Institute of Technology Associate Professor

Environmental
Microbiology

20■ Future policy for improving the water
environment of Shin-Horikawa River①②③

Installing separate sewer system that reduces the pollution
load as wide as possible
Working on sewerage measures that will be effective early
ex：installing rainwater reservoirs
Discharging groundwater and factory cooling water that
supplies oxygen for the bottom of the river
Checking the result of ①, ② and ③ continuously④Water conveyance from the other basin according to theimprovement of water quality at the intake place21

■ Survey and examination for improving thewater environment of the Shin-Horikawa River＜Assumed schedule＞
Separation of sewerage(some sections)【Water and Sewerage Bureau】(Upstream)

Stormwater reservior 【Water and Sewerage Bureau】
Utilization of groundwater【Environmental Affairs Bureau】

Utilization of factory cooling water【Greenification & Public Works Bureau】【Greenification & Public Works Bureau】

Short-term

Medium-term

Conducted an interview survey withriverside operators regarding theamount and quality of discharged
water in FY2021.

Transmission of Raw Waterfrom other water areas

Long term

Short term : 1 to 5 years
Medium term: 5 to 10 years
Long term : 10 years or more22

■ Cooperation with Nagoya Chamber of Commerce（Shin-Horikawa River Future Vision Study Group）
Purpose: Nagoya Chamber of Commerce calls Horikawa River, Nakagawa
Canal, and Shin-Horikawa River as "Nagoya-3 Rivers".
And also "Nagoya-3 Rivers" attractiveness improvement project" is one ofthe priority initiatives for community development. Since Shin-Horikawa
River is the least utilized in "Nagoya 3-Rivers", we are working to formulate avision with academics, citizen groups, riverside companies, etc.

Composition
Committee member

Professor Hideshima, Nagoya Institute of Technology,
HSC Secretary General Hattori
Riverside companies, etc.

ObserverEnvironmental Affairs Bureau-Regional Environment Policies Division
Housing & City Planning Bureau-Community Development Planning Division
Greenification & Public Works Bureau-River Planning Division
Waterworks & Sewerage Bureau-Sewerage Planning Division

Secretariat

Nagoya Chamber of Commerce23

■ Cooperation with Nagoya Chamber of Commerce（Shin-Horikawa River Future Vision Study Group）
Schedule： Orientation cruise in Shin-Horikawa River（May 2021）
Review meeting (scheduled to be held 4 times from July 2021 to February 2022)
Release of Shin-Horikawa River Future Vision (scheduled for late March 2022)

Orientation cruise (May 28)

First Meeting (July 27)

24

Implementation by
Nagoya City
Waterworks and Sewerage Bureau

25Initiatives for clarification ofHorikawa River26

■Initiatives for clarihicationof Horikawa RiverMoriyama water treatment center
Horikawa-river right bank Rain-Water reservoir

Garbage Catcher

Meijo watertreatment
centerAdvanced facilities of primary treatment
Meijo water treatment center
Chitose water treatment center(Under construction)

Rain Water reservoir for pollution control
Ozone Rain-water reservoir
Ozone Rain-water Horikawa-river right bank Rain-Water reservoir
reservoir
Horikawa-river left bank Rain-Water reservoir
Horikawa-river left bank
Set of Garbage removel facilities
Rain-Water reservoir

Horikawa River
Shiratoribashi

Advanced wastewater treatment
Meijo water treatment center (disk filter)

Nakajima pumping station

Shrinkage of Rainwater screen slit
Shiratoribashi pumping station
Nakajima pumping station
Chitose water treatment centerpumping station

Chitose water

Reclaimed wastewater supply
Moriyama water treatment centertreatment center
Garbage Catcher（Corporation withGreenification & PublicWorks Bureau）
27

■ Advenced wastewater treatment◆ Meijo water treatment center(wastewater treatment capacity：50,000m3/day）Started operation in 2010

ＳＳAfter
installation

mg/l
3.3

Significant decrease
11

1

Minute Suspended Solids(SS) in treatedwater are removed more by the filtration
devices (disk filter)
28

■Advanced Facilities of primary treatment（Improvement of combined sewer system)
We changed the primary treatment of rain water from Settling treatment toFiltration treatment , remodeled the part of existing first settling basin andinstalled advanced facilities of primary treatment in the water treatment centers.

◆ Meijo Water Treatment Center （primary treatment capacity 99,400m3/day）・Started operation in 2019
◆ Chitose Water Treatment Center （primary treatment capacity 84,900m3/day）・Construction started in 2021

◆Removal Rate of BOD 20%-30%➡50%-60% Improvement

29

■Rain-water Reservior for pollution controll（Improvement of combined sewer system）
We construct rainwater storage facilities to reduce pollution load for
Horikawa River in rainy weather by storing high polluted first flush
rainwater temporarily.
Ozone rain water
Reservoir forpollution control

Horikawa-river right bankRainwater
Reservoir forpollution control

Horikawa-river left bankRainwater
Reservoir forpollution control

Started operation in 2006

Started operation in 2010
（13,000m3）

Started operation in 201930
（14,000m3）（12,000m3）

■ Removal and Reduction of inflow of pollutants◆Improvement of combined sewer system(Installation of Garbage Removal Device)
BeforeThe number of installation ofGarbage Removal Device (end of FY2020)
Total Plan

InstalledFuture plan to install

127

125

2

Wastewater
Treatment Plant

Overflow

Garbage Removal
DeviceAfterGarbage in sewerage
overflows together
with rainwater

Wastewater
Treatment Plant

Overflow•Rainwater treated by thegarbage removal devices
overflow into river•Removed garbage is treated at
Wastewater Treatment Plant
together with sewerage31

■Shrinkage of Rainwater screen slit
（Improvement of combined sewer system)
Rainwater screens are the facility to remove comparatively big garbage,and installed in water treatment centers and pumping station.
More garbage is removed by shrinkage of rainwater screen.
◆Shiratoribashi pumping station
Nakajima pumping station
Chitose water treatment center◆Rainwater screen slit
４０mm → ２５mm
◆Prevention of inflow of pollutants

32

■Supply of reclaimed wastewaterMoriyama water treatment center supply
reclaimed water treated by membrane
filtration to Horikawa river.

Moriyama water
treatment center

Water supply :Up to 4,000m3/day(0.046m3/s)

Shonaiirrigation

Flat membrane unit
aerobic tank

Flat membrane unit

Horikawa river※Watering period is almost irrigation period（April〜October）（Except the period for Shonai irrigation channel（November〜March））

33

Initiatives for clarification ofShin-Horikawa River34

■Initiatives for clarification of Shin-Horikawa River
Improvement facilities ofcombined sewer system inWakamiya avenue Rainwater reservo

Horidome water treatment

Advanced wastewater treatment
Atsuta water treatment center (AO method)
Fukue Rain-waterreservoir

centerShin-Horikawa river

Takatuji Rain-water
reservoir

Takakura pumping
stationAtsuta water treatment center

Ushimaki pumping
stationTenmacho water treatment
centerAdvanced facilities of primary treatment
Horidome water treatment center
Tenmacho water treatment center
Rain-water reservoir for pollution control
Wakamiya avenue Rain-water reservoir
Fukue Rain-water reservoir
Takatuji Rain-water reservoir
Set of Garbage removel facilities
Shrinkage of Rainwater screen slit
Takakura pumping station
Ushimaki pumping station
Tenmacho water treatment center(under installing)35

■Advenced wastewater treatment◆ Atsuta water treatment center (AO method)
Final
Sewage treatment capacity：about 38,000m3/day sedimentation
Reactor tank

tank

NH3

P

NH3

下水NH3NH3P P P
POSPPOSNH3:Organic
Substance:Phosphorus:Ammonia

PPPPPAirPsludge
Anaerobictank

Aerobic
TankTo sludge treatment center

The process can remove nitrogen and phosphorus which causes
eutrophication more than normal conventional activated sludge
process.

36

■Advanced Facilities of primary treatment（Improvement of combined sewer system)
We changed the primary treatment of rain water from Settling treatment toFiltration treatment , remodeled the part of existing first settling basin andinstalled advanced facilities of primary treatment in the water treatment
centers.

◆Tenmacho Water Treatment Center （treatment capacity 168,000m3/day）・Started operation in 2011
◆Horidome Water Treatment Center （treatment capacity 277,200m3/day）・Started operation in 2018

Treatment flow

Special filteration materilal◆Removal Rate of BOD 20%-30%➡50%-60% Improvement!

37

■Rain-water Reservior for pollution controll（Improvement of combined sewer system）
We construct rainwater storage facilities to reduce pollution load for
Shin-Horikawa River in rainy weather by storing high polluted firstflush rainwater temporarily.
Improvement facilities of combined sewersystem
in Wakamiya avenue Rain-water reservoir

Takatuji Rain-water

Fukue Rain-water

reservoir

reservoir

Started operation in 1987

Started operation in 1999

Started operation in 2002

（30,000ｍ3）（26,000ｍ3）（19,000ｍ3）
38

■Removal and Reduction of inflow of pollutants◆Improvement of combined sewer system(Installation of Garbage Removal Device)
BeforeThe number of installation ofGarbage Removal Device (end of FY2020)
Total Plan

Installed

Future plan to install

45

45

completion

Wastewater
Treatment Plant

Overflow

Garbage Removal
DeviceAfter

Garbage in sewerage
overflows together
with rainwater

Wastewater
Treatment Plant

Overflow•Rainwater treated by thegarbage removal devices
overflow into river•Removed garbage is treated atWastewater Treatment Plant
together with sewerage

39

■Shrinkage of Rainwater screen slit
（Improvement of combined sewer system)
Rainwater screens are the facility to remove comparatively big garbage,and installed in water treatment centers and pumping station.
More garbage is removed by shrinkage of rainwater screen.
◆Takakura pumping station
Ushimaki pumping station
Tenmacho water treatment center◆Rainwater screen slit
４０mm → ２５mm
◆Prevention of inflow of pollutants

40Additional initiatives for clarification

41

■Further water clarification
In the upper and middle area of Horikawa
and upstream area of Shin-Horikawa
We are trying the following measures mainly now.

①Measures which show the effectearly, such as the construction ofrainwater trunk sewer which has thefunction to retain the non-treatedsewage temporarily before overflow
to the river.
②Sewer separation at the model
district.（Sewer separation at theUrban development using thelimited area.）waterfront(Horikawa)42

Implementation by
Nagoya City
Environment Bureau

43

■Examination of groundwater conduction plan to Shin-Horikawa Riverin FY2020

Image of groundwater use
Discharging groundwater from bottom layer is expected to improve water quality< main effects >- Improvement of dissolved oxygen concentration in thebottom layer.
- Reduction of stratification.
( Difference in salinity between surface and bottom layers)

High Water
Level
Tokyo Peil
1.20m
Low Water
Level
Tokyo Peil
-1.37mTreated water (+untreated water)

Seawater coming in
at high tide

Hydrophilic spaceor oxygendissolution
equipment, etc.

Groundwaterflow

Seawater is always
stagnant

River bed

Well P
44

■Investigation about using ground water inShin-Horikawa（2021）
In 2021, we are investigating
geological features in theriverside area of Shin-Horikawa.
.

Investigation spot
Investigation spot
Maizuru Bridge
Uzura Bridge
Kinen Bridge

Utsugi Bridge

Fujimi Bridge
Ooi Bridge
Mukaida Bridge
Shinonome Bridge

Horagai Bridge

45

Thank you for your attention

46