Transcript Roles of Dams for the Future in Japan

Japan Commission on Large Dams
Roles of Dams for the Future in Japan
Topic 3.2 Session 3.2.3 in the 5th World Water Forum
March 20, 2009
Michio OTA
Japan Commission on Large Dams (JCOLD)
Lead Specialist of Water Resources Engineering
Japan Water Agency （JWA)
Contents
1. Condition of Water Affairs in Japan
2. Roles of Dams up to the present in Japan
3. Roles of Dams for the Future in Japan
4. Roles of Dams for the Future in the World
with regard to Food Security
Contents
1. Condition of Water Affairs in Japan
Rivers and Precipitation in Japan
Temp.
Tokyo
Precipitation
30
(mm)
400
20
300
10
200
0
100
（℃）
-10
1 2 3 4 5 6 7 8 9 10 11 12
0
Annual mean rainfall: 1,700mm
Source: Ministry of Land, Infrastructure, Transport and Tourism, MLIT
Comparison of Riverbed Gradients
Elevation
(m)
Rivers in
Japan
Rivers in Continents
Distance from river mouse (km)
Source: MLIT
Feature of Rivers in Japan is,
- huge difference in the condition between flooding time and normal time
- the water flow out soon after the flooding time
Tone River
Kiso River
Yodo River
Mississippi River
Thems River
Danube River
Source：MLIT, Annual Report of Flow Rate（1984～1993）
Tokyo after the war in 1945
Source: Prof. Tuneaki Yoshida, Tokyo Univercity 7
Tokyo in 2008
Source: http://bluestyle.livedoor.biz/
Periods according to the Change of Economic Condition
GDP (Trillion YEN)
600
Pop. (Million)
14
500
140
12
120 400
10
100
80
60
Population
8
300
200
GDP
6
4
2
40
20
DGP growth rate (%)
100
0
Source: MLIT
0
0
-2
1950
1960
1970
1980
1990
2000
9
Serious Water Shortage in Metropolitan Area
Supply trough Water Tank Truck
Pollution in Urban River
Smelled badly and no fish
In 1960s to early 1970s
11
Changes Over Time in Ground
Subsidence
GL
Cumulative ground
subsidence (cm)
0m
0
Minamiuonuma (Yokawa, Muika Town, Niigata Prefecture)
-50
-100
Chikugo / Saga Plains (Yokote, Shiroishi Town, Saga Prefecture)
Kanto Plain (Higashiowa, Washinomiya Town, Saitama Prefecture )
Nobi Plain (Hakke, Nagashima Town, Mie Prefecture)
-150
-200
Niigata Plain (Sakai, Niigata City, Niigata Prefecture)
-250
Osaka Plain (Hyakushima, Nishiyodogawa Ward, Osaka)
-300
Source: http://www.ara.go.jp/arage/keisei/keisei02.html
-350
1970
-400
Kanto Plain (Kameido, Koto Ward, Tokyo)
4.5m -450
2000
1990
1980
1970
1960
1950
1940
1930
1920
1900
1910
1890
-500
Flood Disaster
Tokyo area hit by Kathleen Typhoon in 1947
Source: MLIT
Flood Disaster
12
Inomori-cho, Tenpaku-ku, Nagoya city in 2000
Normal condition
Struck by the disaster
“Source: MLIT
Contents
2. Roles of Dams up to the present
in Japan
Agricultural Water
Manno-Ike Pond:
Presented by Manno-Ike Land Improvement District
Change of Farm Land Area and Population
In Japan
Source: National Land Agency
Percentage of Active Storage Capacity of Irrigation
Ponds and Dams in Japan
(a supply area of 2 ha or more)
Agricultural Water
Total Active Capacity： 2,999,712×103 m3
Total Supply Area： 1,225,882 ha
１０％
Number of Ponds and Dams：63,591
２４％
-1868
1868-1912
1912-1926
1926-1945
1945unknown
９％
４７％
７％
３％
Source: Ministry of Agriculture, Forestry and Fisheries, MAFF
Transition of Water Supplied Population and Average Life Expectancy
18
Water supplied population (ten thousands)
Average life expectancy
1995
1990
1980
1970
1960
1950
1940
1930
1920
1910
1900
1890
Dam water utilization capability of
the water supply
Source: MLIT
Average life expectancy (years)
Water supplied population
1883
Water utilization capacity of dam (hundred thousands m 3)
Domestic Water
Energy for Water
Changes of Electric Power Production at the Early Stage
Source: Electric Power Civil Engineering Association
Energy for Water
Comparison of Electric Power Source
Flood
Control
Flood
Control:
Mitigation of Flood Disasters in Japan
Number of Dams in Japan
Capacity of Flood Control Dams
Death Toll by Floods
3500
3000
2500
2000
Old River
Law mainly for
flood control
River
Law for multi-purpose
objectives
1500
1000
6,000
5,000
4,000
3,000
New River Law
inclusive of
environmment
and ecology
500
0
2,000
1,000
0
1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
21
Data source:国交省水害統計、ダム年鑑(1999); Graphed by Imamura & Yoshida
Annual Death Toll by Floods (person)
Total Number of Dams ('000)
Flood Control Capacity (million m3)
4000
Japan has around 2,800 dams which heights are
over 15m.
Dams have played a critical role for Japanese
socioeconomic development based on increase of
food production, supply of electric power,
development of water for domestic and industrial
use and improvement of safety level of flood
control especially in large cities.
Contents
3. Roles of Dams for the Future
in Japan
Variability of extreme events is increasing due to climate change
Source: MLIT
( mm ) Climate Change In
2,100
2,000
1,900
1,800
1,700
1,600
1,500
1,400
1,300
Average rainfall trend
1,200
1,100
Japan
Annual Precipitation
Variability
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Estimation of the snow depth at 100 years from now
• Because of the global warming, at 100 years from now, it is predicted that there will be almost no
snow in West Japan
• At the Sea of Japan side, it is predicted that the area which has the greatest snow depth of 100cm
or more will be narrowed drastically
Distribution map of greatest snow depth in cooling season
Present
100 years later
Climate Change
legend
legend
less than 1cm
less than 1cm
from 1cm to less than 5cm
from 1cm to less than 5cm
from 5cm to less than 10cm
from 5cm to less than 10cm
from 10cm to less than 20cm
from 10cm to less than 20cm
from 20cm to less than 50cm
from 20cm to less than 50cm
from 50cm to less than 100cm
from 50cm to less than 100cm
from 100cm to less than 150cm
from 100cm to less than 150cm
150cm and more
150cm and more
Source: “Estimation of change of snow under global environmental change” Inoue Satoshi, Yokohama
Kotaro, National Institute for Agro-Environmental Sciences
4
Changes in water supply capacity of the Kiso River System.
Population Projections for Japan: 2006-2055
Source: National Institute of Population and Social Security Research in Japan
Virtual Water
• Japan indirectly uses other countries’ water resources through the import of foods etc
• The trend in trade will also have impact on the future water demand and supply in Japan
Japan’s total import amount of virtual water
Others
Virtual water poured in
Japan by import item
(billion m3/year )
Corn
Soybean
Wheat
Rice
Barley
Beef
Pork
Chicken
Milk and dairy products
Industrial products
Self-sufficiency rate in food is 40%
Total import amount: 64 billion m3/year > Japan’s domestic consumption of irrigation water: 59 billion m3/year
Source: Calculation of the research group of Oki assistance professor at Institute of Industrial Science,
University of Tokyo, based on the demand and supply of foods etc.
7
Contents
4. Roles of Dams for the Future
in the World with regard to Food
Security
Predictions of the future world population and grain production
Source: Water Resources Dept. MLIT
Conclusion
1. Secure Food Production in Japan
Japan should increase more food production domestically
and ensure stable supplies of food in the future.
A stable supply of irrigation water must be ensured by
storing unstable river flow with irrigation ponds and dams.
2. Water for Energy in Japan
Japan should have a policy to restrict emission of CO2.
Hydropower is a clean and 100% domestically produced
recyclable energy in Japan.
Dams for hydropower generation will contribute to the above.
Conclusion
3. Climate Change Adaptation in the view of Dams in
Japan
Abnormal phenomena of heavy rain and serious drought
et al. will be caused by global warming and make a
greater impact on water supply in the future.
Using Dams is one of the effective climate change
adaptations.
However, new dams will not being smoothly constructed
in Japan, thus the burden on existing dams will continue
to rise. The priority issues are redeveloping existing
dams and reorganizing of existing dams to optimize their
operations.
Conclusion
4. Roles of Dams for the Future in the World with regard
to Food Security
Need of world grain production in the near future will
increase demand for agricultural water.
Further expansion of cultivated land and improvement of
deteriorated farmland including overgrazing of grassland,
land of salt accumulation caused by excessive pumping of
grand water and so must be done especially in developing
countries. These factors will increase the need for
development of new water resources to supply irrigation
water.
Thank you for your kind attention
Tama River around 1970
Photo: Environment Bureau,
Tokyo Metropolitan Government