Measures to makeHorikawa River Limpid

Implemented by Nagoya City

February 25th, 2012
Nagoya City Greenification & Public Works Bureau
Rivers Department River planning Division1

■Reserve additional
water resource
Moriyama Water
Treatment Center◆Apply reclaimed wastewater
Conduct 4,000m3 water in a day(maximum) into Horikawa River which isreclaimed from wastewater by membrane
filtration at Moriyama Water Treatment
CenterNew line for
applying reclaimed
wastewater

Shonai
irrigation ditch

Horikawa
River

Conducting line into
Horikawa River※Reclaimed water applies during irrigationseason (April – October)2

■Reserve additional headwaters;
investigation and examination about use of groundwater◆The left bank of Horikawa River, Seko inMoriyama ward
Possibility of pumping up water from the shallow
underground is under investigation and examination
at the upstream section of Horikawa River
Upstream section ofKizune Bridge
Sanage Bridge
Nagoya castle
Meijo park

Koshio Bridge
Upstream section of
Naya Bridge Tsujie Bridge

Shimizu WAKUWAKU
Water（ground water）

Instances of using shallow groundwater

The pump-up test is under going fromFeb.20123

■Making shore scenery;development of promenades (completed in Nov. 2011)◆The left bank of Horikawa River, upstream of Nakatsuchido Bridge
To make the shore scenery with the sense of river-park unity, promenade andplants are installed.

Sanage Bridge

Meijo park

Nagoya castle
Koshio Bridge

Naya Bridge

4■Making shore scenery;development of promenades (scheduled to complete in Mar. 2012)◆The left bank of Horikawa River, between
Sanage Bridge and Shiga Bridge
To create continuous useful space between Meoto
Bridge and Tabata Bridge (2.2km long), promenade isbuilding at downside of Sanage Bridge.

Sanage Bridge
Nagoya castle

Meijo park

Koshio Bridge

5■Activity Support for events◆Participating in events
Participating in the executive of Horikawa Flower Festival in spring andHorikawa Water Magic Festival in autumn.

■Improvement of the water quality
Making rapid and pool
◆The upper Horikawa River(unaffected section by the tide）
The monotone flow of the river will
be diversified by placing wood posts
and stones , self-purification of theriver will be improved by making
cover .

post

monotone flow

post
post
stone
diversionary flowstoneImage■ Removal of Water Pollution
The method of cleaning up suspended garbage◆Removal of stagnant suspended garbage in the middle-down stream area of the Horikawa River

Install the gate and the garbage collecting basket
by remodeling the storm overflow chamber (sewage weir)④garbage collecting basket

Drain the rainwater

Pick up the collectedgarbage regularly for thedisposal

in case of heavy rain

garbage collectingbasket

suspended garbage

下水処理場へwater
treatment

etagcenter①

Catch floating garbage by the fence byusing tidal river flow toward up anddownstream

Collect the garbage inmaertspu

catching fence↑↓gate③ the basket

Horikawa

Sewage (combined sewer)②

Collect floating garbage when thegate gets open automatically based on
the water level.

maertsnwod

■ Removal of Water Pollution
Combined Sewer Overflow Control（wet weather）◆ Reservoir Construction
Rain-water reservoirs for pollution control are constructed for the reduction of sludge generation by controlling
outflow of highly polluted first flush, decreasing the fluency of overflow at storm overflow chamber, alleviating
rapid deterioration of water quality in wet weather, and decreasing the stagnant pollution load of the river●Ozone Rain-water Reservoir（12,000ｍ3completed in 2006）●Horikawa Ugan Rain-water Reservior forpollution control（13,000ｍ3, completed in 2010）●Horikawa Sagan Rain-water Reservoir for pollution control（14,000ｍ3now under construction）

ShonaiHorikawa River Map

RiveriveaR

Investigation Point
Sanage Bridge●
by the City
Kitashimizu Bridge●rInjection Point of TRWKR

2219Meijo Park
Nagoya Castle

HabashitaBridge●Motoiri SlicewaydYa

41

Horikawa River●Koshio Bridge

Shin247

Horikawa Tide Gate

１

●Minatoshin Bridge
Yamazaki River

Nagoya PortoyaNagetsu
Meit LineMain

Kizaemon Bridge●23erRiveLIin
Main

Shirotori Bridge

aikaw
HorSumiyoshoBridge

dookai
JR TNakagawa
Canal

JR Tokaido Shinkansen

Oto Bridge ●１JRMatsushige
Lock Gate

ChuoM

HoridomeainLine●Naya Bridge

Nagoya Station

Oe RiverResult of the survey of BOD (Biochemical Oxygen Demand)(Average from Sep. to Dec.)
mg/L

65

4.1

4.5

4.342006

2007(2nd stage )2008(4th stage )2009(6th stage )2010(8th stage )2011(10th stage )5.8

3.7 4.0

3.6

3.5

3.0

2.93

2.22

2.6

1.9

2.9

2.4 2.4

2.2

2.3

1.82.11.7

1.6

1.2

1.6

1.7

1.9

2.8

2.2

2.3

1.7

1.7

1.3

10
SanageBridgeInjection
導水箇所point

MotoiriSliceway

Kitashimizu Koshio
BridgeBridgeNayaBridge

Kizaemon Minatoshin
OtoBridge Bridge
Bridge※Every Survey was conducted at the ebb of the neap tide.

Result of the survey of BOD (Biochemical Oxygen Demand)(Average from Sep. to Dec.)
mg/L

Before
TRWKR

654

4.6
4.1

4.5

3.6

3

During TRWKR

After
TRWKR

4.0
2.7
2.7 2.62.3

2

3.6
2.2

2.0

1.9

3.0
2.7
2.5
2.2 2.12.02.3 2.4
2.0
1.9
1.7

10
SanageBridgeKitashimizu Koshio
BridgeBridge

導Injection
水箇所point

MotoiriSliceway

NayaBridge

Kizaemon
Oto
Bridge Bridge※Every Survey was conducted at the ebb of the neap tide.

Minatoshin
BridgeResult of the survey of DO(Dissolved Oxygen)(Average from Sep. to Dec.)
mg/L

12

10.1

9.4

108

9.1

8.9

7.5

7.7

8.0

7.9

7.6

6.9

6.9

2006

2007(2nd stage )2008(4th stage )2009(6th stage )2010(8th stage )2011(10th stage )

7.3
6.0

6

5.7

5.0

5.4
5.6

4.6

4.9

4.14.44.3

3.84

3.2

3.7

3.0
1.92

2.1

2.8

2.52.41.30
Injection point

SanageBridgeKitashimizu Koshio
BridgeBridge

導水箇所

MotoiriSliceway

Naya
BridgeKizaemon
Oto
Bridge Bridge※Every Survey was conducted at the ebb of the neap tide.

Minatoshin
BridgeResult of the survey of DO(Dissolved Oxygen)(Meanvalue from Sep. to Dec.)
mg/L

1098765432
10

8.3 8.4
7.5 7.2 7.7

Before
TRWKR

8.9

After
TRWKR

During TRWKR

8.4
6.9 7.2
5.6
3.8
3.2

Injection point

SanageBridgeKitashimizu Koshio
BridgeBridge

導水箇所

MotoiriSliceway

4.6
3.6
3.0

Naya
Bridge4.0
3.1
1.9 1.7

4.3 4.3

2.5 2.4
1.3

Kizaemon
Oto
Bridge Bridge※Every Survey was conducted at the ebb of the neap tide.

minatoshin
Bridge