Flood Analysis in Geum River& Countermeasure Establishment

the 8th Hydro Asia 2014

Hydraulic and HydrologySession 1

Total Water Service Provider K-water

21 Climate Change in Korea

1

In 100 years : Temp. 5℃ ↑, precipitation 17% ↑

2 times more than global warming

0.74℃

[Change of Global Mean Temp.]

1.7℃

[Change of Mean Temp. of Korea]

(Source : KMA, Institute)

Climate Change in Korea

Water management under Changes & Challenges

Frequency, Intensity of Flood & Drought in-crease

- Flood damage (billion Won) : 123.6(’71)→1,990.4(’05)

Evaportranspiration & Water demand etc. in-crease

Regional rainfall deviation & uncertainty in-creaseTyphoon intensity & Heavy rain increase

- Typhoon intensity : 984→960hpa, 24hpa↓/36yr- Heavy rainy days : 20→31days, 11days↑/50yr

1 Climate Change in Korea

Total Water Service Provider K-water

22Climatic & Geographical Characteristics in Korea

The 70’s : 1,225mm → Recently : 1,465mm, 19.6% ↑

Since the 1970, drought with every 5-7 years

Annual Precipitation : 1,277mm

2 Climatic Characteristics – Precipitation trends

895

1977

1982

1988

1994

2001

2008

1,007

1,001

953

1,061

1,016

1,383

1,409

1,736 1,611 1,6691,791 1,908

Trough : 817.5㎜ (60.7%)Monsoon : 327.0㎜ (24.3%) Typhoon : 201.4㎜ (14.9%)

Trend

5yr 6yr 6yr 7yr 7yr

1465mm

1225mm

Effective Water management is absolutely required

Trough : 362.5㎜ (41.4%) Monsoon : 321.8㎜ (36.7%) Typhoon : 191.8㎜ (21.9%)

Precipitation During Summer Season (JJAS) : 876.1 ㎜ (65% of the Total)

2 Climatic Characteristics – Monthly precipitation

Annual Precipitation : Global 1.6 times Water per Capita : Global 1/6 times

1,277

2,629

534 201,364

715 22,741

807 16,427

867 7,7941,690 4,933

1,220 4,907627 4,530

2 Climatic Characteristics – Water per capita

Mountainous with

Steep slope

Korea land

Seasonal discharge variation is very severe(Flood season : much water flood,⇒ Dry season : small water drought)⇒

= Raito of Max/Min River discharge

90260

190270

13022

834

1830

3114

0 50 100 150 200 250 300

HanNakdong

KeumSeomjin

YoungsanYangtze Thames

SeineRhein

NileMississippi

Yodo

Coefficient of regime

2

Water per capita

Geographical Characteristics

Total Water Service Provider K-water

23Geum Gang River & GRRP(River Restoration Project)

3 Geum Gang River & GRRP(River Restoration Project)

3 Geum Gang River & GRRP(River Restoration Project)

Youngju dam

Hwasun

Damyang

Han Riv.

Seomjin Riv.

Nakdan

Youngsan Riv.

ChilgokGangjeongGoryeong Dalseong

Hapcheon Changnyeong

Changnyeong Haman

GangcheonYeoju

Ipo

SeungchonJuksan

Dam Weir Flood Retention Res.

BarrageExpansion

Introduction of GRRP

Andong-Imhaconnection

Gumi

Sangju

Bohyeondam

Nakdong Riv.

BarrageExpansion

Project Dredging : 43 million ㎥ Multi-purpose Weir : 3

Bank Reinforcement : 117 ㎞ Embanking Agr. Res. : 30

Farmland Remodeling : 17

Small Hydro-power : 3

Eco-stream : 199 ㎞ Bike Road : 301 ㎞

Basin Area : 9,912 ㎢ , Basin Length : 397 ㎞

Geum Riv.

Baekje

Sejong

Gongju

3 Geum Gang River & GRRP(River Restoration Project)

Riverbed and Water Level Profiles of the Geum River

Estuary barrage Daecheong dam

Sejongweir

137 ㎞

GongjuweirBaekje

weir

24.2MCM15.5MCM

5.7MCM

length

depth

3 Geum Gang River & GRRP(River Restoration Project)

Status of Weirs in the Geum RiverSejong-weir Gongju-weir Baekje-weir

Weir Length(m) 348 280 311Capacity(106 m3) 5.7 15.5 24.2

Hydropower plants Capacity ( ㎾ ) 2,310 3,000 2,640

Fishway(ea) 1 2 1

Sejong-weir Gongju-weir Baekje-weir

Total Water Service Provider K-water

24 TEAM PROJECT

4 TEAM PROJECT

MISSION

□ Find various solutions to flood problems at target areas

□ and Verify your solution !

4 TEAM PROJECT

Target area

4 TEAM PROJECT

Target area

AREA 1 AREA 2

AREA 1

4 TEAM PROJECT

NO. 21+000

NO. 21+660

Length : L=2,860m (No. 18+550 ~ No. 22+650)Bank top level: Right(7.75m~9.16m), Left(-)

Flood Level : EL. 6.76m ~ EL. 7.47m (100year return period)Cultivated Land Altitude: EL. 3.70m ~ EL. 3.75m

FLOW

AREA 1

4 TEAM PROJECT

NO. 21+000

NO. 21+660

Problems : Sudden river narrows, Non-bank area(left side)- Frequent flooding at cultivated land

- River bed sedimentation at direct downstream by Bottleneck phe-nomenon- Oppose the river improvements by local residents

Riverbed sedimenta-

tion

FLOW

Non-Bank area

AREA 2

4 TEAM PROJECT

Length : L=1,890m (No. 26+740 ~ No. 28+630)

Bank top level: Right(8.55m~9.23m), Left(10.00m~10.36m)

Flood Level : EL. 8.01m ~ EL. 8.35m (100year return period)

BANK

BANK

AREA 2

4 TEAM PROJECT

BANK

BANK

Problems : Sudden river narrows

- Concerned about right-bank erosion by speedy flow veloc-ity- River bed sedimentation at direct downstream by Bottleneck phe-nomenon

• DEM at target areas

□ Modeling Analysis using 1-D(HEC-RAS,…) & 2-D(CCHE-2D, MIKE,..) tool

Go! Go! Go! Move! Move! Move!

□ Given data :

• A river bed measurement data (CAD-type)

• Frequency flood discharge at target point

• Other necessary data for analysis..

□ Segregation of duties

Go! Go! Go! Move! Move! Move!

TEAM Target area Remarks1 Area12 Area23 Area14 Area25 Area16 Area2

- Elemental analysis => joint execution(3 teams)- Find solution => each team- Verify solution => each team

□ 1 target area for 3 teams

Go! Go! Go! Move! Move! Move!

We want your creative idea !