Measures to makeHorikawa River Limpid
Implementation by Nagoya City
Feb.23rd 2019
Greenification & PublicWorks Bureau
River Plannning Div.
Waterworks and Sewerage Bureau
Sewerage Plannning Div.
Environment Bureau
Local environmental measures Div.
1

Implementation by
Greenification & PublicWorks Bureau

2◆Removal of Sludge①Sludge have been dredged only 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 timeThis project is going to be
carried out aroundGojo-Bridge area (2018-)
Nayabashi Area

OtoBridge

・Sludge of 155,000m3 have been removed in the past
・The removing of sludge is continuing
around the Oto Bridge.

SumiyoshiBridge
Shin-Horikawa River
Confluence：現在の断面①Dredging 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
Installed in2010

Before (2009)

Installed in2013

Installed in2012

After (2013)

Installed in 2015
(Downstream of Ruriko Bridge)

Before (2015）

After (2013)

Before (2011)

After（2016）

Before（2015）

MallardJapanese mitten crab

Little egret

After (2015)

Installed in 2016
(Downstream of Meoto Bridge)

Some of the creatures seen in the upstream of Horikawa River

Pale chubBefore (2012)

After（2016）◆Improvement・Variety and amount offish have increased.
（example pale chub)・Benthos have increased.
（example shrimp)
・Plants have grow upmore.

5◆Construction of Shallows and Depths (Plan)
City of Nagoya will construct and install shallows and abyss toupstream of Kizune-Bridge in Kita Ward before March 2019.

Horikawa River

Current condition

Kizune-Bridge
Area to be constructed

Chigonomiyajindo-Bridge
66

◆ Use of shallow groundwater
Use of shallow groundwater in theupstream area of Horikawa River①

2013.Mar.

②

Tsujie Bridge
0.01m3/s

Uprsteam of Seko Bridge

0.01m3/s③

2005.Nov.

2004.Oct.

④2014.Mar.

①★
②
Kizune Bridge
Sanege Bridge③Sanage Bridge/s
0.01m0.01m /s④
2015.Mar.
2008.Mar.
⑤⑥⑤⑥ ★：Survey Point (fy 2019)⑦ (Upstream of Kurokawa⑧No.1 Bridge)
Meijo Park
3Shiga Bridge
0.01m3/s

Nagoya castle⑦

2018.Mar.

Kinjo Bridge
0.01m3/s

3

Shimizu wakuwaku
0.0005m3/s
2016.Mar.

⑧

Nakatsuchido Bridge
70.01m3/s◆Attention signboard installation
Attention signboard installed around the Naya Bridge

8◆Attention signboard installation
Installation location diagram（all 10 places）
天王崎橋上流右岸広場
納屋橋きらめき広場

みのりの広場
ＮＳTennouzakiBridge

シャムズガーデン

納屋橋ゆめ広場

ピア納屋橋【船着場】

錦橋下流左岸広場

旧加藤商会ビル・・・Signboard setting place

9◆Removal of sludge in Shin-Horikawa River
Horidome Water
Treatment Center
Miyano-Watashi Port(River confluence)

Shinsuzaki Bridge
MaizuruBridge

Horikawa River

Nakagawa Canal

Shin-UchidaBridge

Synodic Mean Low Water Level(T.P.-1.4)

Ukishima Bridge

Oi Bridge

TateishiBridge

Oi Bridge

Maizuru Bridge

Thickness:about 2m

MukohdaBridgeRiverbed of Shin-horikawa River (After Removal of Sludge)【gradient. 1/10000】

TateishiBridge

Hataya Bridge

ShinhoritaBridge

Shiratori Bridge

HinodeBridge

Shin-Horikawa River

Sumiyoshi Bridge

Range 400m

Removal of slude completedThickness:about 0.8m

Horidome WaterTreatment Center

Removal of Sludge inupstream zone wascompleted in Feb. 2019.

Removal of Sludge in upstream zone
was completed.

Ukishima Bridge
UchidaBridge
Nagoya Port
…Location of Sedimentary Sludge10◆Removal of sludge in Shin-Horikawa River

State of dredging
11

Implementation byWaterworks and Sewerage Bureau

12■Removal and reduction of inflow of pollutants◆Advanced water treatment
at the Meijo Water Treatment Center（since May 2010）
mg/l
After installation

3.3Significant
decreaseＳＳ

Average :1.0 or less1

Less than 1 Less than 1

Minute Suspended Solids(SS) in treated water
are removed more by the filtration devices13

■ Removal and reduction of inflow of pollutants◆Control of combined sewer overflow（Installation of advanced primary treatment facility）
Advanced primary treatment facilities at maintained area by combined sewer system
will be installed in order to improve water quality of primary treatment in rainy weather.

◆Meijo Water Treatment Center・Started construction in 2017
・Scheduled to start operation in 2019

Fig.1 Process flow in Temma-cho Water Treatment Center

Pic.1 Special filter material

14

■Removal and reduction of inflow of pollutants◆Control of combined sewer overflow（rainwater storage facility）
Construct rainwater storage facilities to reduce pollution load for
Horikawa River in rainy weather by storing high polluted first flush
rainwater temporarily.
Ozone Storm water
Reservoir forpollution control

Horikawa Ugan
Rainwater
Reservoir forpollution control

Started operation in 2006

Started operation in 2010
（13,000m3）（12,000m3）

Horikawa Sagan
Rainwater
Reservoir forpollution control

Under construction
since 200815（14,000m3）

■Removal and reduction of inflow of pollutants◆Horikawa Ugan
Rain-water Resevoirfor pollution control

Horikawa Ugan Rainwater
Reservoir for pollutioncontrol
Started operation inSeptember 2010
･About 13,000㎥

・Started operationin September 2010
・About 13,000㎥
Cumulative stored water
volume in FY2017
About 710,000㎥

NagoyaCastleHorikawa Sagan
Rainwater
Reservoir forpollution control（14,000m3）
Scheduled to start
operation in 201816

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

The number of installation ofGarbage Removal Device
Total plan

Installed by theend of 2017

Future plan toinstall

126

112

14Before

Garbage RemovalDevice
Overflow

Wastewater
Treatment Plant

Garbage in sewerage
overflows together
with rainwater

AfterWastewater
Treatment Plant

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

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

garbage basket

Sanage Bridge
inflow gate

capturing fence

The exterior Garbage catcher

Meijo Park
Nagoya CastleCross Section

Result of collection in 2015 １．４ t
Result of collection in 2016 １．３ t

Koshio Bridge
Naya Bridge

Result of collection in 2017 ０．８ t
Result of collection in 2018 １．０ t

At the end of December18

■Additional Water Resource◆Utilization of Reclaimed Wastewater(Excluding Winter)
Conducting reclaimed wastewater treated by membrane
filtration at the Moriyama Water Treatment Center
Water Supply： Up to 4,000m3/day（0.046m3/ｓ）

Moriyama Water
Treatment Center

Flat membrane
unit aerobic tank
(400sheets×12units)

Shonai Irrigation

Upper stage membrane case(200 cartridges inside)
Horikawa RiverLower stage membrane case(200 cartridges inside)
Flat membrane unit

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

19

Implementation by
Environment Bureau

20

■ Examination survey for river clarification
Shin-horikawa
新堀川 River

Ozone
Layer
大曽根層

TurumaCentral Library
鶴舞中央図書館

大曽根層
Ozone
Layer

Basic survey to effectively use
ground water as source of theriver and water quality
improvement◆Application of ground water forclarification
21

■ Application of ground water for clarification
About Shin-Horikawa that has water quality problem,
We will conduct a basic survey to effectively use groundwater as source of water quality improvement.

In order to securewater source
In order toimprovewater quality□ Information gathering
・Boring data
・Water leaketc.

□Consideration of model case22