Measures to makeHorikawa River Limpid
Implementation by Nagoya CityFeb.29th 2020
Greenification & PublicWorks Bureau
River Plannning Div.
Waterworks and Sewerage Bureau
Sewerage Plannning Div.
Environment Bureau
Local environmental measures Div.
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Implementation by
Greenification & PublicWorks Bureau

2◆Removal of Sludge in Horikawa River①Sludge have been dredged on water route
between the Shiga Bridge and Shin-Horikawa
River confluence (1994-2007)②Construction of Bank Protection in River management project
Kurokawa Area
Nagoya Castle③After Bank Protection Works, River bed Excavation andremoval of sludge are implemented at the same time

This project have been carriedout aroundGojo-Bridge area (2018-)
Construction of bank protection+ Removal of sludge

Speed Up of Construction of Bank Protection！

Nayabashi Area

OtoBridge

SumiyoshiBridge
Shin-Horikawa River
Confluence①
Dredging of Sludge on Water Route② Bank Protection Works③ River Bed Excavation andRemoval of Sludge at the same time3◆Ｃｏｎｓｔｒｕｃｔｉｏｎ 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
Construction in 2016
（Downstream of Meoto Bridge）

4

◆Construction of Shallows and Depths
Construction Plan in Downstream of
Shin-Hori-Bridge in Kita Ward,2020

Horikawa River

Current condition

写真撮影

Shin-Hori-Bridge

Tsujie-Bridge

5◆Ｃｏｎｓｔｒｕｃｔｉｏｎ of Shallows and Depths
Installed in2010

Before (2009)

Installed in2012

After (2013)

Installed in 2015
(Downstream of Ruriko Bridge)

Before (2015）

After（2016）

Before (2011)

Installed in2013

After (2013)

Installed in 2016
(Downstream of Meoto Bridge)

Before（2015）

After（2016）

MallardJapanese mitten crab

Little egretAfter (2015)

Installed in 2018
(Upstream of Kizune-Bridge)

Before（2018）

Some of the creatures seen in the upstream of Horikawa River

Pale chubBefore (2012)

After（2018）◆Improvement
・Variety and amount offish have increased.
（example pale chub)・Benthos have increased.
（example shrimp)
・Plants have grow upmore.
6◆ Use of shallow groundwater
New pumping groundwater facility is now underconstruction in upstream of Kurokawa No.1 Bridge.

①

2013.Mar.

2004.Oct.

②

Tsujei Bridge
0.01m3/s

Uprsteam of Seko Bridge

0.01m3/s①★
②③
Sanage Bridge④⑤ ★：2019 Consruction⑥ (Upstream of Kurokawa⑦No.1 Bridge)⑧
Meijo Park
Nagoya castle

写真撮影

③

2005.Nov.

Kizune Bridge
0.01m3/s⑤

2015.Mar.

Shiga Bridge
0.01m3/s⑦

2018.Mar.

Kinjo Bridge
0.01m3/s

2014.Mar.

④

Sanege Bridge
0.01m3/s⑥

2008.Mar.

Shimizu spring water
0.0005m3/s
2016.Mar.

⑧

Nakatsuchido Bridge
70.01m3/s

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

garbage basket

garbage basket
pollutants

Sanage Bridge
inflow gate
inflow gate

capturing fence

The exterior Garbage catcher

Meijo ParkCross Section

Nagoya Castle
Koshio Bridge
Naya Bridge

8■Removal of pollutants
Cooperation with Cleaning group of ports (Sei-ko-kai）

9■ Collection of pollutantsｔResult of collection

Cooperation withCleaning groupof ports(Sei-ko-kai）

Garbagecatcher※temporary value

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■Examination for water environment improving (2020）○Basic Examination for water environment improving
Verify the effects of various water cleaning measures＜Examples＞
Securing water source(underground water)

headrace

Shin-Horikawa River

Horikawa River（Ex.）Spring water in
TsurumaiLibrary

Waterworks andSewerage Bureau（Ex.）Horikawa-Ugan rainwater
reservoir for pollution controll

Nakagawa Canal

Environment Affairs Bureau

Separating sewer systems､ 〇Securing water source(convey Horikawa River water)“Hybrid sewerage”

Greenification &Public Work Bureau（Ex.）Image of convey
water from Horikawa River○Hearing with Experts etc.
Examine the effective water cleaning measures and future
utilization of waterfront area
Experts ：Experts in river, water quality, city planning, etc.
Contents ：・effective water cleaning measure and scale・future role of waterfront

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■Cooperation with Nagoya Chamber ofCommerce and Industry （2020 plan）○To make prosperity of Shin-Horikawa River
together with companies on the river・Experience event of boarding （know the present）
・Exchanging opinions about the future （talk about the future）

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Implementation byWaterworks and Sewerage Bureau

13Initiatives for clarification ofHorikawa river

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■Initiatives for clarihicationof Horikawa riverMoriyama water treatment center

Advanced water treatment
Meijo water treatment center (disk filter)
Advanced facilities of simple treatment
Meijo water treatment center

Horikawa-river right bank Rain-Water reservoir

Rain Water reservoir for pollution control
Ozone Rain-water reservoirGarbage Catcher
Horikawa-river right bank Rain-Water reservoir
Ozone Rain-water Horikawa-river left bank Rain-Water reservoir
reservoir
Meijo water
Horikawa-river left bank
Set of Garbage removel facilities
treatment
Rain-Water reservoir
centerShrinkage of Rainwater screen slit
Shiratoribashi pumping station
Nakajima pumping station
Horikawa River
Chitose water treatment center

Shiratoribashi
pumping station

Chitose water

Nakajima pumping station
Reclaimed wastewater supply
Moriyama water treatment center

treatment center
Garbage Catcher（Corporation withGreenification & PublicWorks Bureau）
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■Advence water treatment◆Meijo water treatment center(treatment capacity：50,000m3/day）ＳＳ
mg/l

After installation

3.3

Significant
decreaseLess than 1 Less than 1

1

Minute Suspended Solids(SS) in treated water are
removed more by the filtration devices (disk filter)
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■Advanced Facilities of simple treatment（Improvement of combined sewer system)
We changed the simple treatment of rain water from Settling treatment toFiltration treatment , remodeled the part of existing first settling basin andinstalled advanced facilities of simple treatment in the water treatment
centers.

◆ Meijo Water Treatment Center （simple treatment capacity 99,400m3/day）・Started operation in 2019

Treatment flow

Special filteration materilal※Left figure is Tenma Water Treatment Center◆Removal Rate of BOD 20%-30%➡50%-60% Improvement!

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■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 201918
（14,000m3）（12,000m3）

■Removal and Reduction of inflow of pollutants◆Improvement of combined sewer system(Installation of Garbage Removal Device)

The number of installation ofGarbage Removal Device (end of 2018)

Total Plan127

BeforeWastewater
Treatment Plant

Overflow

Installed Future plan to install112

15

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 at
Wastewater Treatment Plant
together with sewerage

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■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

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■Supply of reclaimed wastewaterMoriyama water treatment center supplyreclaimed 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））

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Initiatives for clarification of
Shin-Horikawa river22

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

Horidome water treatment

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

centerShin-Horikawa river

Takatuji Rain-waterreservoir

Takakura pumping
stationAtsuta water treatment center

Ushimaki pumping
stationTenmacho water treatment
centerAdvanced facilities of simple 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 stationUshimaki pumping station
Tenmacho water treatment center(under installing)23

■Advenced water treatment◆ Atsuta water treatment center (AO method)
FinalSewage treatment capacity：about 38,000m3/day sedimentation
Reactor tanktank

NH3P

NH3

下水NH3NH3

P P PPOSPPOSNH3:Organic
Substance:Phosphorus:Ammonia

PP

PP

P

AirP

sludgeAnaerobictank

Aerobic
Tank

To sludge treatment center

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

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■Advanced Facilities of simple treatment（Improvement of combined sewer system)
We changed the simple treatment of rain water from Settling treatment toFiltration treatment , remodeled the part of existing first settling basin andinstalled advanced facilities of simple 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※Left figure is Tenma Water Treatment Center◆Removal Rate of BOD 20%-30%➡50%-60% Improvement!

25

■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）
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■Removal and Reduction of inflow of pollutants◆Improvement of combined sewer system(Installation of Garbage Removal Device)

The number of installation ofGarbage Removal Device (end of 2018)

Total Plan45

BeforeWastewater
Treatment Plant

Overflow

Installed Future plan to install

41

4Garbage 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 at
Wastewater Treatment Plant
together with sewerage

27

■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(under installing)◆Rainwater screen slit
４０mm → ２５mm
◆Prevention of inflow of pollutants

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Additional initiatives for clarification

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■Further water cleaning in upper-middle areaof Horikawa and upper area of Shin-Horikawa
Problem〇Need to implement the measures for watercleaning in near future and examine future
separating sewer system to contribute todevelopment of downtown area utilizing
waterfront.

Measures（Image）
Shonai RiverN

Yada River

Measures

OzoneStationＴMeijo〇Examination of rainwater reservoir
connecting to rainwater main sewer trunkfor integral pollution control
as well as continuous treatment ofrainwater in wastewater treatment center.

ＴHorikawa River〇Construction of rainwater main sewer
trunk and closure of rainwater dischargec h ambe r o f c om bin e d se we r alo n g
Horikawa River and Shin-Horikawa River,anticipating future sewer separation.

NagoyaCastleＴＴ

TsuyuhashiNakagawa
Canal

Horidome

Wastewater Treatment
CenterDiversion WeirSewer Pipe（Combeined）
Rainwater Pipe（including untreated wastewater)

Matsushige
BridgeStorage Pipe

Shin-Horikawa
River30

Implementation byEnvironment Bureau

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■Examination of ground water use for river clarification（2020）
Area of examination

Ozone
Layer

Shin-Horikawa River

Ozone Layer（abundant ground water）◆Examination of ground water
use in Shin-Horikawa◆Survey for visualization ofwater cycle of Yamazaki River
We will be conducted to promote riverclarification by effective use ofground water.
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Securewatersource！

◆Examination of using ground waterin Shin-Horikawa River

Improvewaterquality！

Examination will be conducted how to convey groundwater intoriver in upper Shin-Horikawa area where ground water isabundant

2019□ Basic Survey
Some model cases are constructed
and considered for clarification of
Shin-Horikawa River withinformation of ground water.
・Conveyance of spring water,
rainwater,
and underground water leakage
・Boring well and flowing welletc.

2020□ Preparation for the plan of
conveying ground water into ShinHorikawa River, which is judged
possible to utilize in basic survey
・Route・Quantity
・Creation of waterfront areaetc.
□ Comparative examination ofwater quality improving effect etc.
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