Impact of Climate Change on Water Resources of Nepal …€¢ Case study • Result ... mass of dead...

Impact of Climate Change on Water Resources

of Nepal and Role of WECS

Gautam Rajkarnikar Project Coordinator, Koshi River Basin Management Program

Water and Energy Commission SecretariatGovernment of Nepal

E mail: [email protected] Dialogue in Nepal 14 December 2010Kathmanu, Nepal

Outlines of Presentation

• Brief Introduction of Water and Energy Commission

Secretariat ( WECS )

• Country background

• Water sector Scenario

• Temperature and Precipitation Trend

• Glacier Scenario

• Case study

• Result

• Conclusion

Water and Energy Commission (WEC) and its

Secretariat (WECS)

• The Water and Energy Commission (WEC) was established by

Govt.of Nepal in 1975 with the objective of developing the

water and energy resources in an integrated and accelerated

manner. Consequently, a permanent secretariat of WEC was

established in 1981 and was given the name, Water and

Energy Commission Secretariat (WECS).

• The primary responsibility of WECS is to assist Govt. of Nepal,

the Ministry of Energy and other related agencies in the

formulation of policies and planning of projects in the water

and energy resources sector. This also works as central water

planning unit of Govt.of Nepal. The objectives and mandates

of WEC and WECS have been revised and modified a number

of times since their establishment.

Composition of Water and Energy Commission

The composition of the Water and Energy Commission is as follows:

• Minister for Energy - Chairperson

• Members

• Member, National Planning Commission(Water Resources)

Secretary, Ministry of Water Resources

• Secretary, Ministry of Finance

• Secretary, Ministry of Physical Planning and Works

• Secretary, Ministry of Industry

• Secretary, Ministry of Commerce and Supplies

• Secretary, Ministry of Law, Jusice and Parliamentary Affairs

• Secretary, Ministry of Agriculture and Cooperative

• Secretary, Ministry of Foreign Affairs - Member

• Secretary, Ministry of Environment

• Secretary , Ministry of Science and Technology

Composition of Water and Energy Commission

Contd..• Secretary, Ministry of Forest and Soil conservation

• Secretary, Ministry of Local Development

• Two persons nominated by Government from known water resources and

energy specialist from non-Government sector -

• Dean Institute of Engineering, Tribhuvan University

• President Nepal Engineers' Association

• Representative, Federation of Nepalese Chamber of commerce and Industry

• Secretary, Water and Energy Commission Secretariat- Member Secretary

• WECS is now looking for a new partner to take on the emerging challenges

together in the area of water and energy sector planning and policy

formulation

Objectives of the WECS

• To provide assistance to the concerned ministries in formulating

policies and objectives to be included in the perspective/periodic

plan relating to the water resources and energy sector.

• To provide suggestions, recommendations and guidance with

regard to the multipurpose (mega and medium scale only)

projects’ development as well as to irrigation, hydropower,

drinking water, industrial use of water, flood management and

water navigation; and also regarding the promotion and

development of such mega and medium scale projects, and

protection of environmental aspects relating to the above

sectors.

• To formulate policies and strategies with regard to the water

resources and energy sector.

• To render opinion, advice and recommendations on bilateral and

multilateral issues relating to water resources and energy.

The Mandate of WECS

• To formulate necessary policies and strategies for conducting

study, research, survey and analysis on various aspects of

water resources and energy development in keeping with the

priorities and targets of GON.

• To enact the necessary laws pertaining to the development of

water resources and energy.

• To establish coordination among national and sectoral policies

relating to water resources and energy sector.

• Identify the viable power projects and make an analysis of

bilateral and multilateral projects relating to the development

of water resources and energy.

Location of Nepal

Hydro-physiology of Nepal in Brief

• There are more than 6000 rivers and lakes within the territory of Nepal

• Total drainage area: 194,471 km2

• Three Class of Rivers: Snow fed, Rain fed and Seasonal

• Annual surface flow 225 billion m3

• High altitude variation from 60 m in Terai (Jhapa) to 7,500 m in high Himalayas within a span of 200 m in average.

• High Temporal variation (time) of annual rainfall, i.e., 20% of total annual rainfall from October to May (8 months) and 80% from June to September (4 months).

9

10

Legen

Kathmandu

CHINA

Langtang

Annapurna

Kanjuroba

Simara

Mt Everest

Trans Himalaya

High

Himalaya

Midlands

Mahabharat Range

Siwalik RangeTerai

Physiography

11

Annual Mean Temperature °C

80 81 82 83 84 85 86 87 88

27

28

29

30

-18 -12 -6 0 6 9 15 21 27

Map of Glaciers and Glacier Lakes Distribution

ICIMOD/UNEP (2000)

Water Sector Scenario

• Nepal has 225 billion cubic meters of water available

annually.

• About 15 billion cubic meters has been used for

economic and social activities.

• About 10% of total precipitation falls as snow( UNEP,

2001)

• About 23% of total areas of Nepal lie above

permanent snowline of 5000m( MOPE, 2004)

• About 3.6% of total areas are covered by glaciers.

Water Sector Scenario contd..

• 30% of the global glaciers

• 3,252 glaciers covering an area of 5,323 sq. km

• 2,323 identified glacial lakes covering an area

of 75.7 sq. km

Water Balance of Major River Basin

Climate Change

• The United Nations Framework Convention on Climate Change (UNFCCC), in its Article 1, defines “climate change” as: “a change of climate which

is attributed directly or indirectly to human

activity that alters the composition of the global

atmosphere and which is in addition to natural

climate variability observed over comparable

time periods” .

Temperature Trend in Nepal

• IPCC AR4 projects the global temperature to

rise by 1.1 to 6.4 degrees celsius, in an

average 1.8 to 4 degree celsius

• Analysis of 32 years observed data (1975 –

2006) in Nepal shows a temperature increase

of 1.8 degrees celsius

Temperature Trends

R e g io n al M e a n T em pe ra tu r e T ren d s fo r th e pe rio d 1 977 - 94 ( °C pe r ye a r)

S ea s ona l A nnu al

R e g io ns W in ter P re -m onsoon M ons oon Po s t-m onsoon Jan

D ec - Fe b M ar -M ay Ju n -S ep O c t-N o v

T ra ns -H im alay a 0 .1 2 0 .0 1 0 .1 1 0 .1 0 0 .0 9

H im ala ya 0 .0 9 0 .0 5 0 .0 6 0 .0 8 0 .0 6

M idd le M oun ta in s 0 .0 6 0 .0 5 0 .0 6 0 .0 9 0 .0 8

S iw a lik 0 .0 2 0 .0 1 0 .0 2 0 .0 8 0 .0 4

T er a i 0 .0 1 0 .0 0 0 .0 1 0 .0 7 0 .0 4

-0.09 -0.05 0.00 0.05 0.09

0.00

82 84 86 88

Longitude (oE)

Color Coding of temperature trends

(oC year-1)

Spatial Distribution of max. Temperature TrendsLangtang (3920 m a.s.l.)

Precipitation

-3

-2

-1

0

1

2

3

1960 1970 1980 1990

b) Himalaya W

-3

-2

-1

0

1

2

3

1960 1970 1980 1990

c) Himalaya E

-3

-2

-1

0

1

2

3

1960 1970 1980 1990

d) Middle Mountain W

-3

-2

-1

0

1

2

3

1960 1970 1980 1990

e) Middle Mountain E

-3

-2

-1

0

1

2

3

1960 1970 1980 1990

f) Terai/Siwalik W

Years

1960 1970 1980 1990-3

-2

-1

0

1

2

3g) Terai/Siwalik E

Years

-3

-2

-1

0

1

2

3All-Nepal All-Nepal Smoothed

1950 1960 1970 1980 1990

a) All-Nepal

Not trends, only oscillations

このイメージは、現在表示できません。

Annual Mean Temperature for Nepal, 1961-96

y = 0.0697x + 17.92

R2 = 0.7483;

n = 119; 72 < h (m) < 4100

17.00

18.00

19.00

20.00

21.00

1961 1963 1965 1967 1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995

Year

Temperature (deg C)

Hydrometeorological observations across Nepal

Hydrometeorological observations across Nepal

このイメージは、現在表示できません。

Annual MeanTemperature from

high elevation gauges in Nepal, 1976-96

y = 0.1076x + 14.664

R2 = 0.7849;

n = 15; 1800 < h (m) < 4100

14

15

15

16

16

17

17

18

1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996

Year

Temperature (deg C)

Retreat of the Khumbu glacier

2003

Lower, debris covered, part is detached from the upper part and has become a mass of dead ice, which is degrading rapidly, with rapid surface lowering, terminus retreat and ponding in front.

Retreat of the Lirung glacier

Past GLOF in Nepal

No Date River Basin Name of Lake

1 450 years ago Seti Khola Machhapuchhare

2 August 1935 Sun Koshi Taraco, Tibet

3 Sept. 21, 1964 Arun Gelaipco, Tibet

4 Sun Koshi Zhangzangbo, Tibet

5 1964 Trishuli Longda, Tibet

6 1968 Arun Ayaco, Tibet


Source: WECS 1998; DHM; ICIMOD

Past GLOF in Nepal …… contd.No. Date Basin Lake


9 Sep. 3, 1977 Dudh Koshi Nare Tibet

10 June 23, 1980 Tamur Nagma Pokhari, Nepal

11 July 11, 1981 Sun Koshi Zhangzangbo

12 August 27, 1982 Arun Jinco, Tibet

13 August 4, 1985 Dudh Koshi Dig Tsho

14 July 12, 1991 Tama Koshi Chubung

15 Sep. 3, 1998 Dudh Koshi Tam Pokhari

Source: WECS 1998; DHM; ICIMOD

Retreating Process of Nepalese Glaciers

Imja Lake

Tsho Rolpa Lake

• Glaciers are the “Water Tower of Asia” and provide hydrological resource to 1.3 Billion people.

- Himalayan glaciers represent the largest snow cover region on the Earth’s surface outside the poles and make the headwater to major rivers Ganges

- Particularly important for snow/glacier cover is the western Himalayan region.

• Himalayas govern the climate of Asia and significantly influence the onset and strength of the South Asian Summer Monsoon.

- The Indian monsoon accounts for over 70% of the annual rainfall and is directly influenced by the pre-monsoon elevated heating over the Himalayas-Tibetan Plateau and the subsequent land-sea thermal gradient.

Impact of Climate Change on Water

Resource

Specific case of Gandaki River

Basin

Hydrological features of Gandaki River Basin

• Catchment Area : 30,090 km2

• Mean Annual Runoff : 1570 m3/sec.

• Specific discharge :

Maximum: 0.045 m3/sec./km2

Minimum : 0.029 m3/sec./km2

Kali Gandaki at Kotagaon : 11400 km2

Myagdi Khola at Mangalghat catchment area: 1112 km2

Modi khola at Nayapul catchment area : 601 km2

Andhi Khola at Andhimuhan catchment area : 476 km2

Location of River Basins for flow trend analyses

Flow of Myagdi River in January

Station Location : Mangal Ghat , St. No. 404.7

0

24

6

810

12

14

1618

20

1970

1975

1980

1985

1990

1995

2000

2005

Year

Discharg

e (cum

ecs)

Flow of Myagdi River in February


0

2

4

6

8

10

12

14

16

1970

1975

1980

1985

1990

1995

2000

2005

Year

Discharge (cumecs)

Monthly trend of flow observed at the Myagdi River at Mangal Ghat

Flow of Myagdi River in March


0

2

4

6

8

10

12

14

16

18

1970

1975

1980

1985

1990

1995

2000

2005

Year

Discharge (cumecs)

Flow of Myagdi River in April


0

10

20

30

40

50

60

1970

1975

1980

1985

1990

1995

2000

2005

Year

Discharg

e (cum

ecs)


Flow of Myagdi River in May


0

510

15

2025

30

35

4045

50

1970

1975

1980

1985

1990

1995

2000

2005

Year

Discharge (cumecs)

Flow of Myagdi River in June


0

20

40

60

80

100

120

140

160

1970

1975

1980

1985

1990

1995

2000

2005

Year

Discharge (cumecs)


F

Flow of Myagdi River in July


0

50

100

150

200

250

300

350

1970

1975

1980

1985

1990

1995

2000

2005

Year

Discharge (cumecs)

Flow of Myagdi River in August


0

50

100

150

200

250

300

350

400

450

1970

1975

1980

1985

1990

1995

2000

2005

Year

Discharge (cumecs)


Flow of Modi River in May

Station Location : Nayapul , St. No. 406.5

0

5

10

15

20

25

30

35

1988

1990

1992

1994

1996

1998

2000

Year

Discharge (cumecs)

Flow of Modi River in June


0

20

40

60

80

100

1988

1990

1992

1994

1996

1998

2000

Year

Discharge (cumecs)

Monthly trend of flow observed at the Modi River at Nayapul

Flow of Modi River in July


0

50

100

150

200

250

300

1988

1990

1992

1994

1996

1998

2000

Year

Discharge (cumecs)

Flow of Modi River in August


0

50

100

150

200

250

300

1988

1990

1992

1994

1996

1998

2000

Year

Discharge (cumecs)

Monthly trend of flow observed at the Modi River at Nayapul

Flow of Andhi Khola River in May

Station Location : Andhi Mohan , St. No. 415

0

1

2

3

4

5

6

7

1960

1965

1970

1975

1980

1985

1990

1995Year

Discharge (cumecs)

Flow of Andhi Khola River in June


0

10

20

30

40

1960

1965

1970

1975

1980

1985

1990

1995

Year

Discharge (cumecs)

Monthly trend of flow observed at the Andhi Khola at Andhimuhan

Flow of Andhi Khola River in July


0

10

20

30

40

50

60

70

80

1960

1965

1970

1975

1980

1985

1990

1995

Year

Discharge (cumecs)

Flow of Andhi Khola River in August


0

20

40

60

80

100

1960

1965

1970

1975

1980

1985

1990

1995

Year

Discharge (cumecs)

Monthly trend of flow observed at the Andhi Khola at Andhimuhan

Flow of Badi Gad Khola River in July

Station Location : Rudra Beni , St. No. 417

0100200300400500600700

1975

1980

1985

1990

1995

2000Year

Discharge (cumecs)

Flow of Badi Gad Khola River in August

Station Location : Rudra Beni , St. No. 417

0

200

400

600

800

1000

1200

1975

1980

1985

1990

1995

2000

Year

Discharge (cumecs)

Monthly trend of flow observed at the Badi Ghat Khola at Rudra Beni

Impact of Climate Change

• Days and nights are becoming more warmer

• Cool days and nights are turning

lessPrecipitation trend is not as apparent as

temperature but increased trend is indicated

• Number of rainy days with >= 100 mm are

increasing

• Number of rainy days are decreasing

• Extreme events are increasing

Impact on Glaciers

• Glaciers in the Himalayas are retreating fast:

Rikha Samba glacier, AX010, Yala and Imja are

some of the observed.

• Glaciers are retreating very fast from several

meters to 50 meters per year.

Impact on water availability

• Increase in Extreme events (temperature,

precipitation) pose a great threat to the river

discharge.

• Dept. of Hydrology and Meteorology study

showed an increase of 13% more flow on

Karnali River on a 4 degree temperature rise

and 20% precipitation increase.

Impact on Water Sectors

• Extreme weather conditions make the

hydropower projects more vulnerable

• The dry period will invite more uncertainties

on power generation capacity

• Sediment load will also cause problems

Impacts on water sectors contd..

• Drinking water supply will be critical

• Intense precipitation, Increased flood runoff and a great threat:

floods of catastrophic nature, long inundation period, land

degradation,

• land slides, mass wasting, heavy sediment load,Increased soil

erosion.

• Increase in flood and drought magnitude and damages;

Conoclusions• Climatic change affects hydrology of river basin such as

timing of water availability and quantity as well as quality.

• Change in hydrology induce risk to water resources

facilities( flooding, landslide and sedimentation).

• The impact of climatic variability on water resources

depends not only on change in volume and quality but

also on system characteristics.

• Snowfed rivers have early shifting non_ snowfed rivers

have late shifting of hydrograph.

• Climate variability produce excess water in wet period

and less river discharge in dry period .

• The assessments of the climate change impacts are very

essentials for efficient and effective planning of water

resources in sustainable manner.

Thank you.

Impact of Climate Change on Water Resources of Nepal …€¢ Case study • Result ... mass of dead...

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