Measures to makeHorikawa River Limpid
Implementation by Nagoya City
Sep. 29th 2018
Greenification & Public Works Bureau
River Planning Division
Waterworks and Sewerage Bureau
Sewerage Planning Division1◆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 time

This project is going to becarried out aroundGojo-Bridge area (2018-)
Nayabashi AreaOtoBridge・Sludge of 150,000m3 have been removed in the past
・The removing of sludge is continuing
around the Oto Bridge.

SumiyoshiBridge
Shin-Horikawa RiverConfluence：現在の断面①Dredging of Sludge on Water Route② Bank Protection Works③ River Bed Excavation andRemoval of Sludge at the same time2◆Making shallows and deeps
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）

3◆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.

4◆Ｃｏｎｓｔｒｕｃｔｉｏｎ of Shallows and Depths
May in fiscal year 2018, Jyohoku Lions Club had contribute the shallows andDepths to a city at downstream of Kurokawa No.1 Bridge in the north ward.

Ｈｏｒｉｋａｗａ

The state of the site

Meoto Bridge

Installation point
Kurokawa No.1 Bridge

Shinbori Bridge
55

◆Construction of Shallows and Depths
Johoku Lions Club

Kita Public Works Office Manager

Local elementary school students

Presentation ceremony of certificate of appreciation
to Johoku Lions Club6◆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
77◆ Use of shallow groundwater
Use of shallow groundwater in theupstream area of Horikawa River①

2013.Mar.

②

2004.Oct.

Uprsteam ofSeko Bridge
3/s
0.01m
2005.Nov.

Tsujie Bridge
0.01m3/s
2014.Mar.

33③
④
①
★
②③Kizune Bridge
Sanage Bridge
Sanege Bridge
0.01m /s
④0.01m /s
2015.Mar.
2008.Mar.
⑤⑥⑤⑥ ★：Survey Point (fy 2018)⑦ (Upstream of Kurokawa⑧No.1 Bridge)
Meijo ParkNagoya castle⑦

Shiga Bridge
0.01m3/s
2018.Mar.

Kinjo Bridge
0.01m3/s

Shimizu wakuwaku
0.0005m3/s
2016.Mar.

⑧

Nakatsuchido Bridge
80.01m3/s

■Measures of removing sludge in Shin-Horikawa River
Horidome Water
Treatment Center
Miyano-Watashi Port
(River confluence)

Shinsuzaki Bridge
Maizuru
BridgeHorikawa River

Nakagawa Canal

Shin-Uchida
BridgeOi Bridge

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

Ukishima Bridge

TateishiBridgeOi Bridge

Maizuru Bridge
Thickness:about 0.8m

Thickness:about 2m

MukohdaBridgeTateishiBridge

Hataya Bridge

Shinhorita
BridgeShiratori Bridge

HinodeBridge

Shin-Horikawa River

Sumiyoshi Bridge

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

Horidome WaterTreatment CenterRange

Removal of slude completed

Removing sludge as of
September 2018

Removal of Sludge in upstream zone
was started in September 2018.

Ukishima Bridge
UchidaBridge
Nagoya Port
…Location of Sedimentary Sludge

9■ Removal of sludge in Shin-Horikawa River

State of dredging

10

Measures and policies of
Nagoya city Waterworks
and Sewerage Bureau

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

3.3

Significantdecrease

ＳＳAverage :1.0 or less1

Less than 1 Less than 1

Minute Suspended Solids(SS) in treated water
are removed more by the filtration devices
12■ 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

13■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
RainwaterReservoir forpollution control

Under construction
since 200814（14,000m3）

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

Horikawa Ugan Rainwater
Reservoir for pollution
controlStarted operation in
September 2010
･About 13,000㎥

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

NagoyaCastleHorikawa SaganRainwater
Reservoir forpollution control（14,000m3）
Scheduled to start
operation in 201815

■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

After

Wastewater
Treatment Plant

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

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

garbage basket

Sanage Bridge
inflow gatecapturing fence

The exterior Garbage catcher

Meijo Park

Cross Section

Result of collection in 2014 ０．７ t
Result of collection in 2015 １．４ t

Nagoya Castle
Koshio Bridge
Naya Bridge

Result of collection in 2016 １．３ t
Result of collection in 2017 ０．８ t

17

■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 River
Lower 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））

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