Flood Analysis in Geum River & Countermeasure Establishment

1. the 8th Hydro Asia 2014 Hydraulic and Hydrology Session 1 Flood Analysis in Geum River & Countermeasure Establishment

2. 2 Climate Change in Korea 1 Total Water Service Provider K-water

3. 1 0.74℃ 1.7℃ [Change of Global Mean Temp.] [Change of Mean Temp. of Korea] (Source : KMA, Institute) Climate Change in Korea 2 times more than global warming In 100 years : Temp. 5℃ ↑, precipitation 17% ↑

4. 1 Climate Change in Korea Regional rainfall deviation & uncertainty increase Typhoon intensity & Heavy rain increase - Typhoon intensity: 984→960hpa, 24hpa↓/36yr - Heavy rainy days: 20→31days, 11days↑/50yr Frequency, Intensity of Flood & Drought increase - Flood damage (billion Won) :123.6(’71)→1,990.4(’05) Evaportranspiration & Water demand etc. increase Water management under Changes & Challenges

5. 2 Climatic & Geographical Characteristics in Korea 2 Total Water Service Provider K-water

6. 2 Climatic Characteristics– Precipitation trends Annual Precipitation : 1,277mm The 70’s: 1,225mm → Recently: 1,465mm, 19.6% ↑ 1465mm Trend 1225mm 7yr 5yr 7yr 6yr 6yr 1,908 1,791 1,736 1,669 1,611 1,409 1,383 1,061 1,007 1,001 1,016 953 895 1994 1977 1988 2001 1982 2008 Trough : 817.5㎜(60.7%) Monsoon : 327.0㎜(24.3%) Typhoon : 201.4㎜(14.9%) Since the 1970,droughtwithevery 5-7 years

7. 2 Climatic Characteristics– Monthly precipitation PrecipitationDuring Summer Season (JJAS) : 876.1㎜(65% of the Total) Typhoon : 191.8㎜(21.9%) Monsoon : 321.8㎜(36.7%) Trough : 362.5㎜(41.4%) Effective Water management is absolutely required

8. 2 Climatic Characteristics– Water per capita Annual Precipitation : Global 1.6 times Water per Capita: Global 1/6 times Global 16,427㎥/yr Korea 2,629㎥/yr Global 807㎜ Korea 1,277㎜ 534 201,364 Austria 715 22,741 USA 867 7,794 France 1,690 4,933 Japan 1,220 4,907 England 627 4,530 China 2,629 1,277 High population density Korea 807 16,427 Global

9. 2 Runoff Yodo 114 Mississippi 3 Nile 30 Rhein 18 Seine 34 Thames 8 Yangtze 22 Youngsan 130 Seomjin 270 Keum 190 Nakdong 260 Han 90 0 50 100 150 200 250 300 = Raito of Max/Min River discharge Coefficient of regime Geographical Characteristics Geographical Korea land Water per capita Mountainous with Steep slope Seasonal discharge variation is very severe (Flood season : much water ⇒ flood,Dry season : small water ⇒drought)

10. 2 Geum Gang River & GRRP(River Restoration Project) 3 Total Water Service Provider K-water

11. 3 GeumGang River & GRRP(River Restoration Project)

12. 3 GeumGang River & GRRP(River Restoration Project) • Introduction of GRRP Project Dam Weir Flood Retention Res. Han Riv. • 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 ㎞ Ipo Yeoju Gangcheon Youngju dam Geum Riv. Andong-Imha connection Sejong Sangju Nakdan Gongju Baekje Gumi Nakdong Riv. Bohyeon dam Chilgok Gangjeong Goryeong Seomjin Riv. Dalseong Damyang Hapcheon Changnyeong Changnyeong Haman Barrage Expansion Seungchon Barrage Expansion Hwasun Juksan Youngsan Riv. Basin Area : 9,912 ㎢,Basin Length : 397 ㎞

13. 3 GeumGang River & GRRP(River Restoration Project) • Riverbed and Water Level Profiles of the Geum River Sejong weir Gongju weir Baekje weir 5.7MCM 15.5MCM 24.2MCM depth length 137㎞ Estuary barrage Daecheongdam

14. 3 GeumGang River & GRRP(River Restoration Project) • Status of Weirs in the Geum River Sejong-weir Gongju-weir Baekje-weir

15. 2 TEAM PROJECT 4 Total Water Service Provider K-water

16. 4 TEAM PROJECT • MISSION □ Find various solutions to flood problems at target areas □ and Verify your solution !

17. 4 TEAM PROJECT • Target area

18. 4 TEAM PROJECT • Target area AREA 1 AREA 2

19. 4 TEAM PROJECT • AREA 1 NO. 21+000 FLOW 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

20. 4 TEAM PROJECT • AREA 1 NO. 21+000 Riverbed sedimentation Non-Bank area FLOW 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 phenomenon - Oppose the river improvements by local residents

21. 4 TEAM PROJECT • AREA 2 BANK BANK 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)

22. 4 TEAM PROJECT • AREA 2 BANK BANK Problems : Sudden river narrows - Concerned about right-bank erosion by speedy flow velocity - River bed sedimentation at direct downstream by Bottleneck phenomenon

23. Go! Go! Go! Move! Move! Move! □ Modeling Analysis using 1-D(HEC-RAS,…) & 2-D(CCHE-2D, MIKE,..) tool □ Given data : • DEM at target areas • A river bed measurement data (CAD-type) • Frequency flood discharge at target point • Other necessary data for analysis..

24. Go! Go! Go! Move! Move! Move! □ Segregation of duties □ 1 target area for 3 teams - Elemental analysis => joint execution(3 teams) - Find solution => each team - Verify solution => each team

25. Go! Go! Go! Move! Move! Move! We want your creative idea !

26. Thank You