CLIMATE CHANGE IMPACTS AND

FUTURE RESEARCH NEEDS

FOR HYDRAULICS AND

HYDROLOGY ENGINEERS

IWHR’s Global Forum, September 6, 2010

Nobuyuki Tamai

President, International Association for Hydro-

Environment Engineering and Research

Professor Emeritus, the University of Tokyo

Honorary Professor, China Institute of Water Resources

and Hydropower Research

Trend of Global

Warming

All differences are relative

to corresponding

averages for the period

1961-1990. Smoothed

curves represent decadal

averaged values while

circles show yearly values.

The shaded areas are the

uncertainty intervals

estimated form

comprehensive analysis of

known uncertainties (a

and b) and from the time

series (c) (IPCC, 2007)

Impacts of Floods, Typhoons & Cyclones

Number of People Affected by Floods

（annual average, 1980-2000）

Number of People Affected by Typhoons

& Cyclones (annual average，1980-2000）

Water Related Natural Disaster and

the Death Tolls

Regional Distribution

of Floods, 1990-2001

The death toll classified by

income level, 1975-2001

Local Torrential Downpours

Annual Occurrence of Torrential Downpours Higher Than 80mm/hr (average

occurrence per 1,000 observation points)

(Data: Meteorological Agency of Japan, 2009)

Average

1987 to 1997,

11.5 times

Average 1976

to 1986,

9.9 times

Average 1998

to 2008, 18.5

times

Sea level rise

Increase in the frequency of high water events in

Venice between 1926 and 2005 (number of

events equal to and higher than 110cm)

Data: Venice Water Authority Concessionary (2007)

0 10 20 30 40 50 60

1926-1935

1936-1945

1946-1955

1956-1965

1966-1975

1976-1985

1986-1996

1996-2005

Venice and

its lagoon

051208, Yomiuri online

IAHR 2007

Consorzio Venezia Nuova

Venice, The MOSE sytem to

regulate tides in the lagoon

Mobile Barriers and complementary measures (Consorzio Venezia Nuova)

Impact of Climate Change on Flood Risk

The design precipitation in on-going projects was

enlarged in the range of predicted ratios, and the

annual probability of exceedence was calculated.

In flood protection schemes we must estimate

safety level of the target of a master plan. The River

Bureau of Japanese Government performed a

country level simulation by downscaling of the GCM

and Asia Regional Climate Model.

Down-

scaling to

a Country

Model

GCM

Spatial resolution

Atmosphere: 280km

Ocean: Longitude 2.5 deg

Latitude 0.5-2 deg

Asia Regional

Climate Model

Spatial resolution

60km

Japan Regional

Climate Model

Spatial resolution

20km

Subcommittee on

Climate Change

Adaptation for Flood

Control, River Bureau

of Japan (2008)

～200km

Degradation of current projects’ flood safety by Climate Change

Rate of

increase in

precipitation

Flood safety level (annual probability of

exceedence)

Current

Climate

Conditions

Climate Conditions after 100

years (probability under

present climate conditions)

1.1 times

1/100 Comparable 1/50~1/60

1/150 Comparable 1/70~1/100

1/200 Comparable 1/100

1.2 times

1/100 Comparable 1/20~1/40

1/150 Comparable 1/40~1/80

1/200 Comparable 1/60

Subcommittee on Climate Change Adaptation for Flood Control,

River Bureau of Japan (2008)

A Framework of River Basin Management

Model for Adaptation to Climate Change

Step 1 Input Data Meteorology, Geography, Water

Quality, Urbanization, Global

Warming

Step 2 River Basin 2-D Catchment Model, 3-D

Catchment Model, Habitat

Simulation

Step 3 Output Change of Discharge, Flow

Regime, Impact on Ecosystems

Step 4 Evaluation

&

Adaptation

Technical, Economical,

Historical, Cultural Feasibility

Study

Step 5 Engineering

Practice

Design Code, Design Manuals Feed-

back

Research topics in the field of Hydro-

Environment Engineering and Research

1) Prediction techniques of climate change impacts on

hydrological cycle,

2) Climate change impacts on runoff regimes,

3) Climate change impacts on fluvial processes,

4) Impacts of variation of sediment yield on bar

formation and evolution,

5) Climatic impacts on water quality,

6) Climate change impacts on aquatic habitats and eco-

systems,

7) Climate change impacts on floods in lowlands,

8) Adaptation to climate change impacts in mega-cities,

9) Climate change impacts on coastal disasters, and

10) Climate change impacts on groundwater systems in

inland and coastal zones.

Impact of CC (Toshiharu Kojiri, Kyoto Univ.)

GeographyMeteorology

Water Quality

Eco-systems

Urbanization

Global Warming2-D catchment model

3-D catchment model

Change of Discharge

Flow Regime

O il

O il

G as

G as

N uclear N uclear

H ydro H ydro

O ther O ther

C oal/peat

C oal/peat

0%

20%

40%

60%

80%

100%

1973 2007

Other includes

geothermal, solar, wind,

tidal current combustible

renewables (for example,

biomass) & waste, and

heat

Mitigation Options in Energy Production

(IAE ,2009)

Fuel Share of

Electricity

Generation

Big Increase of Renewable Energy,

Waste and Heat

A Possible Mitigation MeasureGenerated electricity by renewable energy, waste & heat is 36.7TWh

in 1973 and 514.0TWh in 2007. In 34years the generated electricity by

renewable energy, waste & heat expanded to 14 times of that in 1973.

Major cause in the difficulties to-date have been intermittent nature

of some major forms of renewable energy.

0 5000 10000 15000 20000 25000

1973

2007

Generated Electricity in one year (TWh)

Renewable energy, waste & heat Total

Potential and Characteristics of

Marine Current Power

The turbine can be raised for

maintenance. Marine Current

Turbines Ltd., Wikipedia (UK)

There is no danger to fish because the

blades rotate quite slowly - about 20

revolutions per minute.

Research suggests marine current

turbines have the potential to be four

times more efficient than wind turbines of

a similar size.

Martin Wright, of Marine Current Turbines Ltd,

said: "We estimate that there is at least 10

gigawatts (=10M Kw) of power available from

tidal power in the UK.

"That's the same as about half of the existing

nuclear industry."

BBC NEWS, 2003 & OCEAN ENERGY & OBSERVATORIES, web.

SeaGen Project

IAHR WG on Marine Renewable Energy was established

in 2009.

The 1.2 MW SeaGen tidal current turbine has been developed

by leading tidal turbines technology developer Marine Current

Turbines Ltd. UK. Unlike wind energy, tidal flows are much

more predictable. Moreover, due to the higher density of water

compared to air, underwater turbines do not need to be as

large as wind turbines. SeaGen has been installed in Northern

Ireland’s Strangford Lough and is the world’s first commercial

tidal current turbine.

NKE Supplies Bearings for Marine

Current Turbines

Wednesday, March 11, 2009

Mitigation Options in Social

InfrastructuresExamples of small scale mitigation plans are considered in the area of

ecological city planning. The topics are concerned with “Light impact way of

life”, such as, rain water harvesting, green roof, non-motorized

transport (cycling, walking), and so on. Technologies and planning are

relevant with “Hydro-Environment Engineering and Research”.

Green Roof in Auckland

Outlet for Rainwater

Rainwater Supply to Plants from a

Parking Lot in Auckland

Medium scale mitigation plans

Examples of medium scale mitigation plans are considered in the area of eco-

compatible river basin management. There are many topics related with

IAHR in river restoration, carbon cycle in a river basin, and so on.

Shibetsu River, Hokkaido, Japan

Straight channelization started in 1967.

Restoration of meanders started in

2001 at a test section.

(a)1945-54 (b)1965-74 (c) 1999

Kushiro Regional Office, Hokkaido Dept., MLIT, Japan

National scale mitigation

An example in national scale mitigation is eco-

compatible management of national

infrastructure planning.

One example is a proposal based on technical

assessment studies on heat island problems

for policy makers.

Subjects in this planning are

1) demand-side management program of water

resources, and

2) environmentally effective land-use regulation.

◎Water Balance

・Suppression of evapo-

transpiration

・Reinforcement of Surface Runoff

Ave. Annual Evapotranspiration

urban center: 300mm

rural Tama area: 800mm

◎Heat Balance

・Reinforcement of Sensible Heat

（heat transport by wind）

・Suppression of Latent Heat

（heat transport by vapor）

◎wate

r B

ala

nc

e

◎He

at

Ba

lan

ce

Urban Heat Island,

simulated results in

Tokyo Metropolitan

Area

(b)Surface Runoff

(a)Evapotranspiration

(a) Latent Heat Flux

(b) Sensible Heat Flux

motto

Think Globally, Act Locally.

Think Scientifically,

Act Professionally.

END

Thank you for your attention.