Natural Disaster Management for Floods Miura Hirohisa

(1)

Natural Disaster Management for Floods

Environmental Seminar, University of Indonesia

7 _{December 2016}

MIURA Hirohisa

JICA Technical Expert for the project on Capacity Development for RBOs in Integrated Water Resources Management in Indonesia

The Project on Capacity Development for RBOs

(2)

-

Comprehensive Structural Measures for Flood in

Japan

-

Flood Control Operation by Several Dams in one

(3)

(4)

River Measures Damage Reduction Measures Basin Measures Water retaining area Water retarding area Lowland area

Preservation of natural / agricultural lands

Flood control ponds

Rainwater storage facilities

Permeable pavements and

rainwater infiltration inlets

Preservation of natural / agricultural

lands,

Restriction of constructing mounds

Drainage facilities

Floodwater storage facilities

Promotion of flood resistant buildings

Warning and evacuation systems

Flood-fighting

Announcement of inundation records and

flood hazard areas

Promotion of flood resistant buildings

Awareness raising of local residents

River Administrator Basin Authority (Prefectures, Municipalities) River Administrator Basin authority

Dams, retarding basins and discharge

channels

River improvement (embanking,

dredging)

Comprehensive Flood Control Measures

(5)

Conservation of natural land

Disaster-prevention reservoirs Embankment control

Facilities for rainwater storage and infiltration

Rainwater storage and infiltration facilities for each house

Maintenance of urbanization control areas

Permeable pavement

Seepage pits River improvement

Multipurpose retarding basin

Rainwater tanks

Rainwater storage in parks

Underground river

Facilities for rainwater

storage and infiltration Construction of drainage pump station Water-proof buildings

River measures River basin measures Damage alleviation measures

Establishment of evacuation warning systems Construction of dams

Comprehensive Flood Control Measures

(6)

River Measures

(7)

River channel improvement

Narrow river cross section

Deterioration of revetment Sedimentation

Earthquake-resistance of levee, Upgrading revetment

Excavation and dredging

(8)

Construction of levees

(9)

Construction & Operation Improvement of Dams

Miyagase dam

Kawaji Dam

関東地方整備局提供

鬼怒川ダム統合管理事務所HPより

Integrated operation of existing dams

Optimum capacity re-division of related dams based on present situations of dam operation, precipitation and flow

characteristics of each sub basin

(10)

Ara River First Retarding Basin

●location：Saitama City & Toda City, Saitama Pref. (28.8 – 37.2km from estuary of Arakawa river)

●Operation Start : Year 2003

●Area of Reservoir : 580 ha

●Total Capacity for Flood Control : 39 mil. m３

●Valid Capacity : 10.6 mil. m3

●Control volume : 850m3_/sec

Retarding basin (Ara river)

Flood Control in Aug. 2006

(11)

Discharge channel (Ara river)

For the Ara River running through Tokyo, a floodway was constructed following

the great flood of 1910.

Construction :1913

–

1930

Length : 22 km

Population in Tokyo city

3.7 million (1920)

12.6 million (2005)

(12)

OtoshifuruTonegawa River

85m3_/s

Kuramatsu River

100m3_/s

Naka River

25m3_/s

Koumatsu River

6.2m3_/s

Showa drainage pump station

200m3_/s

Tone River

The floodway was constructed to drain floodwater in low-lying Naka river basin

(suburban Tokyo), where frequent inundation caused severe damage.

Due to the land restriction, the floodway was build underground.

Underground discharge tunnel (Outer metropolitan area)

Shaft No.5 Shaft No.4

Shaft No.3

Shaft No.2

Shaft No.1

(13)

[Shafts] Shafts Nos. 1 to 5

・Shaft No.1：Inside diameter 31.6m、Depth 71m

・Shaft No.2：Inside diameter 31.6m、Depth 63m

・Shaft No.4：Inside diameter 25.1m、Depth 63m

・Shaft No.５：Inside diameter 15m、Depth 65m

Tunnel in Construction Section No. 4: Inside diameter 10.9m

[Tunnel]

・Length : 6.3km

・Inside diameter : About11m

・Depth : About 50m

Shaft No.3：Inside diameter 31.6m,depth:68m

Pumps

・Maximum discharge 200m3_/s

Gas Turbines x 4 discharge 50m3_/s

Wheel

[Surge tank]

・Length 177m ・Width 78m

・Height 25.4m

・Pillar Number 59、Height 18m

写真：江戸川河川事務所提供 13

Underground discharge tunnel (Outer metropolitan area)

(14)

Basin Measures

(15)

Due to the rapid increase of population, plateaus and hilly areas near large

cities were developed rapidly on a large scale.

1958

Urbanization rate: 10%

1975

Urbanization rate: 60%

1997

Urbanization rate 84.3%

Tsurumi River (Tokyo and Kanagawa Pref.)

Natural area Urban area

The background for the introduction of “Basin Measures”

(16)

Progress of urbanization heighten the risk of flood on low grounds

■

_{Before Development}

Most of rainwater is infiltrated into the ground or reserved in paddy fields: the flow into the downstream is controlled.

■

After Development

Since the surface has been covered by concrete or asphalt, and forests and paddy fields have disappeared, the water flow to the downstream has increased.

The background for the introduction of “Basin Measures”

(17)

normally

Kirigaoka reservoirs

(Tsurumi river)

flooded

Flood control ponds

(18)

Storing rainwater in a schoolyard

Rainwater storage facilities

(19)

permeable pavement

_{permeable tile pavement}

Permeable pavements

(20)

Rainwater storage between buildings in apartment complexes

(21)

Rain Water Infiltration Inlet Trench

Infiltration facilities

Infiltration Inlet

Infiltration trench

Rain Water Infiltration Inlet Infiltration Trench

(22)

Multipurpose retarding basin of the Tsurumi River (Yokohama City)

Before improvement After improvement

Tsurumi River

Multipurpose Retarding Basin

“Multipurpose”: Sports, Park, Nature, Public Facility and Retarding Basin for Flood

Sports Stadium

Park

Nature

Public Facility (City Health Care Center)

(23)

(24)

(25)

Flood Control operation by Several Dams

in one River Basin

(26)

日ダム

淀川三川流点

目ダム

高山ダム

室生ダム

青蓮寺ダム

比奈知ダム

天ヶ瀬ダム瀬田川洗堰

大阪府兵庫県

京都府

奈良県

三重県滋賀県

湖

大阪

京都

桂川下流部の越水箇所

River Basin Area(km

₎

大阪湾

Hiyoshi Dam

Lake Biwa

Seta River

Barrage

Amagase Dam Hinachi Dam Shorenji Dam Murou Dam Nunome Dam

Katsura R.

Kizu

R. Yodo Main R.

Overflowed Point

Uji R.

Kyoto

Takayama Dam

3 Rivers Confluence point

Name Basin Area

km2

Rate %

Lake Biwa

3,848

49.0 Uji R.

506

6.4 Katsura R.

1,100

14.0 Kizu R.

1,596

20.3 Yodo Main R.

807

10.3 Total

7,857 100.0

(27)

For the first time,

E erge cy

weather warning for heavy

rai fall

announced

in Yodo River Basin and 180,000 people received

evacuation advisories.

Total Rainfall

(36hours 3:00, 15

–

_{15:00, 16}

₎

Source: Japan Weather Association

600

500

400

300

200

100

50

0

Rainfall Rader at 05:00 16th _Sep.

Kyoto

Typhoon No.18 in Sep. 2013



Lowest pressure 960hpa



Highest winds 35m/s (162km/h)

Typhoon direction

(28)

Katsura

River

Kizu River

Uji

River

Conducted the

best possible operation with all flood control facilities

to

lower the water level at the 3 rivers confluence point

Amagase

Dam

3 Rivers Confluence Point

(29)

Operations of Seta River Barrage and Amagase Dam

The Flood Water Storage Height :1m

Lake Biwa

Maximum Inflow

Approx.6,000m3/s

湖

Seta River Barrage

▲

Seta River Barrage

Seta River Barrage operated all gates closed

Amagase Dam

On Uji River

(30)

Amagase Dam retaining to its maximum

Amagase Dam

reached approx.

designed highest

Water Level

Uji River

(31)

Operations of Seta River Barrage and Amagase Dam

(Amagase Dam) Hyeto/Hydro

아마가세 댐 유역 평균 시간 우량(㎜)

아마가세 댐 유역 평균 누가 우량(㎜)

Tot

al

R

ai

n

fal

l

일 시

Rai

n

fal

l

50

0

300 1,500

Maximum inflow

1,360m

_/s

Discharge 860m

_/s

SWL 78.5m

80

50

750 In

fl

o

w

/D

isch

ar

g

e

(m

/s)

R

eser

voi

r

W

a

ter

Le

vel

(EL.

m)

Designed Downstream

flow capacity 840m

_/s

Applox. 60%

Amagase Dam reduced the discharge of 500m

_{/s against the maximum}

inflow of 1,360m

_{/s. After that, to prevent overtopping, added discharge}

according to actual downstream condition

21:00, 15th

9:00, 16th

Hourly Rainfall (mm) Total Rainfall (mm)

Applox. Reduce 40% D a te /h o u r 31

(32)

Katsura

River

Kizu River

Uji

River

Hiyoshi

Dam

3 Rivers Confluence Point

Conducted the

best possible operation with all flood control facilities

to

lower the water level at the 3 rivers confluence point

(33)

Hiyoshi Dam retaining flood water that exceeded the SWL

Hiyoshi Dam reduced the discharge of 1,540m

_{/s against the maximum inflow of}

1,690m

_{/s. After that, to prevent overtopping, added discharge according to actual}

downstream condition .

175 185 195 205

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

0 200 400 600 800 1000 1200 1400 1600 1800 0: 00 2: 00 4: 00 6: 00 8: 00 10: 00 12: 00 14: 00 16: 00 18: 00 20: 00 22: 00 0: 00 2: 00 4: 00 6: 00 8: 00 10: 00 12: 00 14: 00 16: 00 18: 00 20: 00 22: 00 0: 00 2: 00 4: 00 6: 00 8: 00 10: 00 12: 00 14: 00 16: 00 18: 00 20: 00 22: 00 0: 00

Maximum Inflow

applox. 1,690

㎥

/s

21:00,

15th

9:00,

16th

21:00,

16th

Maximum Storage EL.201.87m

Maximum

Dischargeapplox.500m

_/s

Exceeded the SWL

NWL in Flood season

EL.178.5m

SWL EL.201.0m

In

fl

o

w

/D

isch

ar

g

e

m

/s

R

ese

rv

o

ir

W

a

ter

Le

vel

(EL.m)

ゲト天端ぎりぎりまで貯留

Applox. 90%

Discharge

150m

_/s

In case of

within SWL

(34)

琵琶湖

Through Emergency flood disaster prevention operation *, water

level of downstream

were not raised .

Hiyoshi

Dam

Ka

A

Ha

Rainfall at Hiyoshi Dam

Hiyoshi Dam

Storage Vol.

21:00

15th 34

Controlled

SWL EL.201.0m

Ka:

Distance 25km

A:

Distance 27km

Ha

:Distance 42km

9:00 16th

21:00 16th

(35)

Katsura

River

Kizu River

Uji

River

5 Dams

Conducted the

best possible operation with all flood control facilities

to

lower the water level at the 3 rivers confluence point

3 Rivers Confluence Point

(36)

5 dams conducted cooperative operation to decrease the water level at the confluence point. As a result, This operation contributed to reduce 70% of Kizu River flow volume.

Kizu

R. Uji R.

HINACHI Dam

MURO Dam

NUNOME Dam TAKAYAMA Dam

320

m3_/s

SHORENJI Dam

170

m3_/s

450

m3_/s

170

m3_/s

50

m3_/s

80

m3_/s

320

_m3_/s

500

m3_/s

1,530

m3_/s

Kyoto

Osaka

Bay

170

m3_/s

Katsura

R.

(37)

5 dams conducted cooperative operation to decrease the water level at the confluence point. As a result, This operation contributed to reduce 70% of Kizu River flow volume.

3 River Confluence Point

Ki

zu

Ri

ver

0 10 20 30 0 500 1000 1500 2000 2500 70 80 90 100 110 120 130 140 2 0 :0 0 2 2 :0 0 0 :0 0 2 :0 0 4 :0 0 6 :0 0 8 :0 0 1 0 :0 0 1 2 :0 0 1 4 :0 0 1 6 :0 0 1 8 :0 0 2 0 :0 0 2 2 :0 0 0 :0 0 0 10 20 30 0 100 200 300 400 500 600 240 250 260 270 280 290 300 310 2 0 :0 0 2 2 :0 0 0 :0 0 2 :0 0 4 :0 0 6 :0 0 8 :0 0 1 0 :0 0 1 2 :0 0 1 4 :0 0 1 6 :0 0 1 8 :0 0 2 0 :0 0 2 2 :0 0 0 :0 0

450m3_{/s to}

480m3_/s

50m3_{/s to}

20m3_/s

600m3_{/s to}

450m3_/s

50m3_{/s const.}

0 10 20 30 240 250 260 270 280 290 300 2 0 :0 0 2 2 :0 0 0 :0 0 2 :0 0 4 :0 0 6 :0 0 8 :0 0 1 0 :0 0 1 2 :0 0 1 4 :0 0 1 6 :0 0 1 8 :0 0 2 0 :0 0 2 2 :0 0 0 :0 0 0 100 200 300 400 500 600 0 100 200 300 400 500 600 240 250 260 270 280 290 300 310 2 0 :0 0 2 2 :0 0 0 :0 0 2 :0 0 4 :0 0 6 :0 0 8 :0 0 1 0 :0 0 1 2 :0 0 1 4 :0 0 1 6 :0 0 1 8 :0 0 2 0 :0 0 2 2 :0 0 0 :0 0 0 10 20 30 0 10 20 30 210 220 230 240 250 260 270 280 290 2 0 :0 0 2 2 :0 0 0 :0 0 2 :0 0 4 :0 0 6 :0 0 8 :0 0 1 0 :0 0 1 2 :0 0 1 4 :0 0 1 6 :0 0 1 8 :0 0 2 0 :0 0 2 2 :0 0 0 :0 0 0 100 200 300 400 500 600

80m3_{/s to}

50m3_/s

300m3_{/s to}

100m3_/s

170m3_{/s to}

80m3_/s

200m3_{/s to}

30m3_/s

(38)

KIZU River

E Dam

D Dam C Dam

B Dam

Coordinated Operation

Decreasing discharge from A Dam

Decreasing Discharge from B, C and D Dams where are located upstream

Moreover, Decreasing discharge from E Dam

↓

Increasing Reservoir Water Level

↓

Water Level is Decreased in KIZU River

and Downstream Usual Operation

Water Level is Increased in KIZU River

A Dam

(39)

(40)

-

Comprehensive Structural Measures for Flood in

Japan

-

Flood Control Operation by Several Dams in one

River Basin

(1)

Katsura

River

Kizu River

Uji

River

5 Dams

Conducted the

best possible operation with all flood control facilities

to

lower the water level at the 3 rivers confluence point

3 Rivers Confluence Point

(2)

5 dams conducted cooperative operation to decrease the water level at the confluence point. As a result, This operation contributed to reduce 70% of Kizu River flow volume.

Kizu

R. Uji R.

HINACHI Dam

MURO Dam

NUNOME Dam TAKAYAMA Dam

320

m3_/s

SHORENJI Dam

170

m3_/s

450

m3_/s

170

m3_/s

50

m3_/s

80

m3_/s

320

_m3_/s

500

m3_/s

1,530

m3_/s

Kyoto

Osaka

Bay

170

m3_/s

Katsura

R.

(3)

5 dams conducted cooperative operation to decrease the water level at the confluence point. As a result, This operation contributed to reduce 70% of Kizu River flow volume.

3 River Confluence Point

Ki

zu

Ri

ver

450m3_{/s to}

480m3_/s

50m3_{/s to}

20m3_/s

600m3_{/s to}

450m3_/s

50m3_{/s const.}

80m3_{/s to}

50m3_/s

300m3_{/s to}

100m3_/s

170m3_{/s to}

200m3_{/s to}

30m3_/s

(4)

KIZU River

E Dam

D Dam C Dam

B Dam

Coordinated Operation

Decreasing discharge from A Dam

Decreasing Discharge from B, C and D Dams where are located upstream

Moreover, Decreasing discharge from E Dam

↓

Increasing Reservoir Water Level

↓

Water Level is Decreased in KIZU River and Downstream

Usual Operation

Water Level is Increased in KIZU River

A Dam

(5)

(6)

Natural Disaster Management for Floods Miura Hirohisa