?. Status of Korea

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Climate Change, Extreme Floods, and Dam Safety in
Korea
Agenda
?. Status of Koreas Water Resources ?. Climate
Change and Extreme Floods ?. Securing Dam Safety
IV. Summary
Kwon, Do-Youp, Vice-Minister, Ministry of Land,
Transport and Maritime Affairs, Republic of Korea
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?. Status of Koreas Water Resources
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Location and Topography

• Korean Peninsula 222,135 ? (South Korea
  100,000?/ forest lands 65.7/ farmland 21.9/
  urban area 5.2, others10 as of 1988 )
• Around 70 of Koreas territory is mountains (?
  Vulnerable to floods)
• Most rivers flow into the West and South Sea

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Precipitation
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Status of Water Resources
Units billion m3/yr
Dry season (20.1)
Rainy season (52.2)
River (12.3)
Reservoir (17.7)
Groundwater (3.7)
Runoff to Ocean (38.6)
Source Long-term Master Plan of Water Resources
(Korea, 06.7.)
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II. Climate Change and Extreme Floods
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Global Warming
Temperature increased by 0.6? during the past 140
years (global aver.) ? The Korean average
increased by around 1.5?
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Changing Climatic Zones
Past Monsoon ? Now Subtropical Climate
(Changes expected in vegetation, fish stocks,
ecosystem) Climate for 20 of territory will
change by 2100
Region Region Changing forest (temperate zones ? subtropical zones)
Vegeta- tion South (temperate) 34.99
Vegeta- tion Middle west (temperate) 16.18
Vegeta- tion Middle east (temperate)  3.16
Vegeta- tion North (frigid zone)  3.11
Fish East and west Sea Subtropical
? Source KEI (Korea Environment Institute,
2003)
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Abnormal Climate
Abnormal climate caused changes in
precipitation patterns for the past 20 years
Ex) Annual Precipitation 7?( 1,166 mm ? 1,247
mm ) Rainy Days 14?(124.9 days/yr ?
107.4 days/yr) Intensity 18?(10 mm/d
? 11.8 mm/d ) Risk management against floods,
droughts, and dam destruction is crucial
Number of days with precipitation
Annual Precipitation
Number of day with precipitation (larger than
80mm/day)
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Increasing Severity of Rainfall
Changes in annual precipitation and number of
annual typhoon is not outstanding. However,
the number of days with heavy rainfall (100 mm
per day and above) rose by 1.5-fold during the
past 10 years (222 times ?325 times)
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Changes is Flood Damage Patterns
Rapid increase of damages Damage in 2000s up
4.5 times (900 M /yr) compared to 70s80s
4.1 B in 2002 Casualty was halved

during same period
Decreasing flooded area but rapid increase of
the damage per unit flooded area (7 times up
compared to 70s80s) due to excessive
urbanization along the river
Casualty
Damage
year
year
Damages per unit flooded area
Flooded area
year
year
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Example of flood damages

• Yeoncheon hydropower plant collapse
• In 1996 due to heavy rain- 700mm in 3 days,
  daily max. 400mm

• Levee failure in Pyeongchang river
• In 2006 hit by typhoon Bilis
• Hourly max. 88mm

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III. Securing Dam Safety
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Dams in Korea

• Present Total of 18,000 dams
• 15 Multi-purpose / 14 Water supply / Others
  (Irrigation, etc.)
• ? Water Supply (17.7 bil.m3/yr), Flood
  Control (2.8 bil.m3)
• Under construction ( 2012)
• 5 Multi-purpose dams
• ? Water Supply (95 mil. m3/yr), Flood Control
  (360 mil. m3)
• Future (2016)
• Build 7 small dams and rehabilitate 2
  agricultural dams
• ? Water Supply (760 M m3/yr)

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Roles of Dams in Korea
Total Storage Capacity 12.9 billion m3
Total Water use33.7 billion m3
Single purpose dam(5)
Groundwater(11)
Irrigation dam(9)
47.2 of drinking water
Accounts for 80.1 of total flood control capacity
Estuary barrage(13)
68.3 of (drinking industrial water)
Dam(52.5)
Stream(36.5)
Multipurpose dam(73)
?Dams are essential in Korea
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Extreme Floods
Recently, PMP surged in dam basins compared to
the former designed value due to Climate Change
? Max. 132 ? in multi-purpose dam basin
632?810mm(Soyanggang dam), 424?561mm(Imha dam)
Max. 317 ? in water supply purpose dam
basin 241?715mm(Yeongcheon dam),
272?863mm(Angae dam) New daily rainfall
record (547?870.5mm/day, 2002.8)
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Flood We must secure the Hydrological Stability
of Dams against extreme flood
(Units million?/yr)
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History of Flood Control Capacity Enhancement
Project

• 2002.8 Typhoon RUSA (4.1bil. loss, 207
  killed)
• 2003.4 ?Flood disaster Prevention and
  Countermeasure Plan? (The
  Office for Government Policy Coordination)
• 2003.4 Presidential Directive (Cabinet
  Council) ? Securing Dam stability against
  extreme flood
• 2003 Launched?Flood Control Capacity
  Enhancement Project ?

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Structural Reinforcement Project for
hydrological stability(Auxiliary / emergency
spillway construction) Total 23 dams
(20032015, 1.3 b) ? 6 completed, 6
under construction, 11 planning Types of
measures - Spilling capacity ? (New,
additional or enlarged spillways) - Dam
storage ? (Parapet wall)
Project Period Project Cost Finished Under Constructing Planning Measure types
0315 (13years) 1.3Billion US Total 23 dams Total 23 dams Total 23 dams Auxiliary/emergency spillway, Enlargement, Parapet wall
0315 (13years) 1.3Billion US 6 6 11 Auxiliary/emergency spillway, Enlargement, Parapet wall
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(ex1) Types of reinforcement
Type2. Open channel spillway
Type1. Tunnel spillway
Type3. Watergate
Type4. Parapet wall
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(ex2) Very large scale Waterway Tunnel
Soyanggang Dam
Two tunnels in row Project cost 0.16 b D14m
L1,280m Q 6,700m3/s
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Imha Dam
Three tunnels in a row Project cost 150
M D15m L420m Q 8,215m3/s
Dae-am Dam
Two tunnels in a row Project cost 40 M D10m
L429m Q 1,633m3/s
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Precipitation has been continuously increasing
in Korea due to climate change, causing massive
damages. Dams play a critical role in Korea but
are threatened by increasingly frequent and
severe floods. Thus, to secure hydrological
stability of dams, the Korean Government launched
Flood Control Capacity Enhancement Project from
2003 which has been successful so far.
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Thank you