The Consistent Development

in the Whole River System

The KANSAI Electric Power Co., INC

Takashi AKIYAMA

IEA :Implementing Agreement for Hydropower Technologies & Programs

Workshop; Best Practices for Renewal and Upgrading of Hydropower Facilities

to Maintain and Provide Value to the Power System, July 18, 2011

July 18, 2011

・History of hydropower development

・Improvement of the river flow

・Redevelopment of existing power plants

■ Integrated management of sedimentation in the Kurobe River system

Contents

■Integrated management of water resources in the Kiso River system

・Sediment

・Flushing Operation

■Consistent development of the whole river system

１

Consistent river-system development involves

setting up a reservoir at the most upper-reach of

the river system for improved river flow,

and making maximum use of the river's elevation

head and water flow to achieve a large peak output

across the whole river system.

Consistent development of the whole river system

The concept in Japan

２

The Sea of Japan

Sho River

Jinzu River

Kurobe River

Kiso River

Osaka Tokyo

0 50km

Lake Biwa

Pacific Ocean

The position of each river system

Osaka

３

・150 hydropower stations

・History of hydropower development

・Improvement of the river flow

・Redevelopment of existing power plants

■ Integrated management of sedimentation in the Kurobe River system

Contents

■Integrated management of water resources in the Kiso River system

・Sediment

・Flushing Operation

■Consistent development of the whole river system

４

Year 1900 ’10 ’20 ’30 ’40 ’50 ’60 ’70 ’80

’90

Waterway-type

Hydropower

development

1910～1920

Dam-type

Hydropower

development

1920～1945

Large dam development

1945～1960

Redevelopment of existing

plants

1960～1980

Consistent development

in the whole river system

Nuclear Hydro

Thermal

Dam-type

Waterway-typeMiura

Dam

The history of hydropower development in the Kiso River５

Electricity

demand

In Japan

Elevation

Maximum

Discharge

1,000MWh

MiuraTakikoshi

Ontake

Tokiwa

Mio

Nezame

Agematsu

Momoyama

Inagawa

Inagawa No.2Suhara

Kiso

OkuwaHashiba Ainosawa

Tako

YogawaYomikaki

Araragigawa

Tsumago

Shizumo

Yamaguchi

Shin’ochiai

Ochiai

Shin’ohi

Ohi

Kasagi

Yaotsu(closed)

Maruyama

Shin’maruyama

Kaneyama

Minokawai

Imawatari

Downstream

Kiso River

Otaki River

Miura Dam

Hydropower Development in Kiso River System

0 5 10 15 20 25(km)

６

Hydropower

32 stations

Total:1,040MW

River channel length: 227km

Catchment area: 9,100km2

Miura power plant

Following the startup of Miura Dam, the annual river flow of

Kiso river was improved as illustrated below

Miura Dam (Miura Power Plant)

Maximum output：7,700kW

Maximum discharge：17.5m3/s

Effective head：54.7m

Flow duration curve for Kiso River

50 100 150 200 250 300 350(days)

(m3/s)

30

15

Maximum discharge of Miura power plant

Before startup of Miura Dam

After startup of Miura Dam

７

Redevelopment of hydropower plant, Kiso & Yomikaki P/S

Following completion of the Miura

Reservoir in 1942, the duration of

Kiso River was improved

Kiso power plant makes use of

surplus river flow which is generated

by operation of Miura Dam

Miura(7,700kW, startup in

1945)

Kiso(116,000kW,startup in 1968)

Nezame

Agematsu

Momoyama

Suhara

Okuwa

Nezame(35,000kW,startup in 1938)

Agematsu(8,000kW,startup in 1947)

Momoyama(24,600kW,startup in 1922)

Suhara(10,000kW,startup in 1921)

Okuwa(12,100kW,startup in 1920)

0 100 200 300

Maximum discharge(m3/s)0 100 200 300

Maximum discharge(m3/s)

Yomikaki No.2(70,000kw，startup in 1960)

Yomikaki#1(42,100kw，startup in 1923)

８

Elevation Elevation

38.40 m3/s

Ookuwa P/S

38.40 m3/s

Ookuwa P/S36.17 m3/s

Suhara P/S

37.57 m3/s

Momoyama P/S

36.17 m3/s

Suhara P/S

37.57 m3/s

Momoyama P/S

48.65 m3/s

Agematsu P/S

48.65 m3/s

Agematsu P/S

65.80 m3/s

Nezame P/S

65.80 m3/s

Nezame P/S

Kiso Dam

Kiso water intake Dam

Kiso P/S

The position of Kiso power plant９

Miura Dam

Kiso water intake weir

New power system with higher efficiency

⇒Prioritized operation

Nezame P/S

bottom

top

Dam

Yomikaki No.2

power plant

: Old system : New system

Weir

Yomikaki No.1

power plant

Development image of Yomikaki No.2 power plant１０

No.1 plant headrace tunnel

Newly constructed

Yomikaki Dam

Redeveloped No.1

plant intake

Newly constructed

No.2 plant intake

Cross-section of No.1 plant intake

Decommissioned part of

No.1 plant headrace tunnel

Optimal use of existing facilities１1

・History of hydropower development

・Improvement of the river flow

・Redevelopment of existing power plants

■ Integrated management of sedimentation in the Kurobe River system

Contents

■Integrated management of water resources in the Kiso River system

・Sediment

・Flushing Operation

■Consistent development of the whole river system

１2

Kurobe Dam

Kurobe No.4

Kurobe No.3

Shin’kurobe No.3

Shin’kurobe No.2

Kurobe No.2

0 5 10 15(km)

Kuronagi No.2

Yanagawara

Aimoto

Otozawa

Kurobe River O River Sasa River

The sea of Japan

Hydropower development in the Kurobe River System

Unazuki

13

Kurobe Dam １4

Kurobe Dam

Height：186m (the highest in

Japan)

Kurobe River No.4 Power

Plant

Maximum output：335,000kW

Maximum discharge：

Seine River

Shinano River

Kiso River

Shou River

0 50 100 150 200 250 300 Distance(km)

Elevation [m]

1500

1000

500

0

Kurobe River Average river gradient : 1/40

River gradient around

the source of the river: 1/20～1/35

River profiles 15

• The amount of inflowing sediment into dams is huge

compared with reservoir capacities.

• It is difficult to transport excavated or dredged materials to

the downstream under the conditions of steep gorge.

A more comprehensive soil management approach is needed.

Background of flushing operation 16

Blocking the flow of sand and soil causes

■raising the riverbed at the upstream

■lowering the riverbed or coastline set back at the downstream

Situation

Slide Gate

Roller gate

Radial gate

Flushing channel

Flushing channel

Upstream Longitudial section

Spillway

gate

Head tank

Power

Station

Catchment area

Name Otozawa

Maximum Output 124MW

Type Concrete gravity

Height 76.7m

Length 136.0m

Total Capacity 9.01 x 106 m

3

Effective Capacity 1.66 x 106 m

3

Operation area 18m

Number 2

Area 5.0 x 5.0m

Upstream Slide gate

Center Roller gate

Downstream Radial gate

Flushing gate

461.18 km2

Power Plant

Dam

Reservoir

Flushing channel

Outline of Dashidaira dam １７

Slide gate

Roller gate

Radial gate

Flushing channel

For maintenance

For flushing control

For prevention of seepage

Moving protection

flame

Flow

Outline of flushing facilities １８

Drawdown

Flushing

through a low-level outlet

Refill

Unazuki Dam

Unazuki Dam

Unazuki Dam

Dashidaira Dam

Dashidaira Dam

Dashidaira Dam

Flushing operation １９

２０

0

100

200

300

400

500

600

700

800

900

Dat

a19

8519

8619

8719

8819

8919

9019

9119

9219

9319

94

1995

/6

1995

/7

1995

/11

1996

1997

1998

1999

2000

2001

2002

2003

/7

2004

/7

2005

/7

2006

/7

2007

/6

2008

/6

2009

/7

2010

/6

Acc

um

ula

ted s

edim

ent

Initial flushing

460,000m3

[x104m

3]

Test flushing

80,000m3

Trial flushing

20,000m3

1995

Huge flood

Emergency flushing

1,720,000m3

Emergency flushing

800,000m3

Emergency flushing

460,000m3

340,000m3

700,000m3

590,000m3

60,000m3

280,000m3

510,000m3

240,000m3

90,000m3

120,000m3

350,000m3

370,000m3

160,000m3

Flushing

Cooperative flushing

Sedimentation volume of Dashidaira reservoir ２１

The end