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CLIMATE CHANGE, ITS IMPACT ON WATER
RESOURCES AND ADAPTATION STRATEGIES
Climate Change
United Nations Framework Convention on Climate
Change (UNFCCC) defines “climate change” as: ‘a
change of climate which is attributed directly or
indirectly to human activities that alters the
composition of the global atmosphere and which is in
addition to natural climate variability observed over
comparable time periods’
R. D. SINGH
DIRECTOR
NATIONAL INSTITUTE OF HYDROLOGY
ROORKEE
General Definition: Any systematic change in the long-term
statistics of climate elements (such as temperature, pressure, or
winds) sustained over several decades or longer.
Climate Change
• Increasing
Temperatures
– Global Warming;
Greenhouse Effect
• Change in
Precipitation Patterns
• Change in patterns of
other climatological
variables
Global surface temperature anomalies
Impact of Climate Change on
Hydrological Cycle…
•
Change in spatial and temporal pattern of
precepitation
• Change in evapotranspiration
• Change in natural recharge pattern
• Change in runoff pattern
Effect of global warming and climate change on hydrologic cycle and
associated extremes
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Climate Change & Runoff
•
Runoff influenced by precipitation,
evaporation and soil moisture.
Consequences of Climate Change
• Temporal and spatial water availability may
be affected (SW and GW)
• High-latitude regions may see more runoff
due to greater precipitation
• Frequent occurrence of Flood and Drought
(Intensity, Frequency and Magnitude )
• Tropics and subtropics regions are
expected to receive less runoff.
• Increase in Glacier retreat rates
• This coincides with the existing water stress
in tropical and subtropical regions
• Reduction in snow precipitation
• Due to sea level rise, problem of sea water
intrusion in coastal areas
IPCC 2001
Climate Related Disasters
S.No
Basin
No of Glacial Lakes
1.
Tons
12
8
2.
Yamuna
GLOF
3.
Bhagirathi
30
A glacial lake outburst flood (GLOF) can occur when a lake contained by
a glacier or a terminal moraine dam fails. The bursting of morainedammed lakes is often due to the breaching of the dam by the erosion of
the dam material as a result of overtopping by surging water or piping of
dam material.
4.
Bhilangana
2
5.
Mandakini
10
6.
Alaknanda
43
7.
Pinder
1
8.
Goriganga
10
9.
Dhauliganga
7
10.
Kutiyangi
4
11.
Beas
59
12.
Chenab
33
13.
Satluj
40
14.
Ravi
17
15.
Taklinga
7
16.
Teesta
266
Sea Level Rise
The adaptation and mitigation process of the GLOFs
can be broadly categorized in the following manner
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•
Creation of a decentralised information system that includes
identification of areas most at risk etc., monitoring and early warning
(and prediction) and support to decision makers in terms of policy
recommendations on adaptation options etc. This will include the
information sharing and experiences dissemination about the early
warning and adaptation measures for the GLOF events at the local
and national levels.
•
Development and testing of adaptation and mitigation measures,
such as land use planning for GLOFs, siphoning, pumping,
excavation of a channel, etc.
•
Building capacity of national, district and local institutions to access
and use this information and measures as well as to provide
information on local indicators/measurements, which would make
the system more interactive and easy to update.
Current sea level rise has occurred at a mean rate of 1.8 mm per year for
the past century,and more recently at rates estimated near 2.8 ± 0.4 to 3.1 ±
0.7 mm per year (1993-2003).
Impacts on coastal areas
Intense Rains and Floods
• Serious and recurrent floods in
Bangladesh, Nepal and India
• Coastal erosion and inundation of coastal lowland as
sea level continues to rise, flooding the homes of
millions of people living in low lying areas
•Rainfall in Mumbai (India), 2005: 1
million people lost their homes
Droughts
•50% of droughts associated with El Niño
• In India, potential impacts of 1 m sea-level rise include
inundation of 5,763 km2
• Significant losses of coastal ecosystems, affecting
the aquaculture industry, particularly in heavily-populated
mega-deltas
•Droughts in Orissa (India) in 2000-2002:
crop failures, mass starvation affecting 11
million people
Cyclones / Typhoons
•Increasing intensity of cyclones formation in Bay of Bengal and
Arabian Sea since 1970
•Cyclone Nargis in Myanmar, 2008: 100 000 deaths
•Devastating Cyclone (Aila) in West Bengal , 2009
National Issues of Interest
Impacts on human health
•Water availability
•How do water fluxes vary on
catchment scale in response to global
climate events?
Endemic morbidity and mortality due to diarrhoeal
disease primarily associated with floods and droughts
•Impacts on Water Quality
•Water Demands
• Crop Evapotranspiration
Exacerbation of the abundance and toxicity of cholera
due to increase in coastal water temperature
•Association of Hydrologic Extremes of
Floods and Droughts with Large Scale
Global Climate Events
Increased deaths, disease and injury due to heat
waves, floods, storms, fires and droughts
India - Water Requirements for Different Uses
(Year 2010)
• Change in Frequency and Magnitude of
extreme events ;
2%
2%
9%
3%
•Impact of year to year variations of the
Monsoon will continue to be dominant
even in the presence of global warming
Irrigation
Domestic
Industries
Power
6%
5%
Navigation
Environment/Ecology
Evaporation
73%
– Design storm intensities - Urban stormwater
drainage
– Delays in onset of monsoon
• Over-year storage policies; Real-time
adaptive decisions
– Salinity Intrusions due to Rising Sea Levels
– Robust & Resilient water management
policies to offset adverse impact due to
climate change
– Change in ground water recharge pattern
• Long term adjustments in policies
====================
– Scale Issues
• Downscaling (space)
• Disaggregtion (time)
– Uncertainty
• GCMs and Scenarios
• Lack of good quality data
GLOBAL CLIMATE CHANGE OVER LAST CENTURY
IPCC (2007) indicated that the average global surface air
temperature increased by 0.74±
± 0.18°C since the late 19th
century. The linear warming trend over the last 50 years
(0.13°C per decade) is twice that for the last 100 years
Temperature anomaly ( o C)
National Issues of Interest (contd)
Source : Ministry of Water Resources, 1999
1.0
1.0
0.5
0.5
0.0
0.0
-0.5
-0.5
-1.0
-1.0
1850
1875
1900
1925
Years
1950
1975
2000
Observed rise in global mean temperature since 1860 relative to the average of observations
over the period 1900 - 1930
Contd..
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GLOBAL CLIMATE CHANGE OVER LAST CENTURY
TRENDS OF CLIMATE CHANGE IN INDIA
Temperature
The extent of snow cover decreased by 10% since
1960s.
The area extent of glacierization in the
European Alps reduced by 30-40%, whereas
the volume of ice reduced by nearly 50%.
Global average sea level rose @ 1.8 mm per year
between 1961 and 2003. The total 20th Century
sea level rise estimated to be 0.17 m.
The trend and magnitude of global warming
over Indian sub-continent over last century
has been consistent with the global trend and
magnitude.
Warming is mainly observed during the postmonsoon and winter seasons.
Mean annual air temperature rose @ 0.57°°C
per 100 years during 1881-1997.(IITM,2004)
Contd..
1.5
1.5
Tem pe ra ture a nom a ly (o C )
Linear Trends = 0.57oC/100 yr
1.0
1.0
0.5
0.5
0.0
0.0
-0.5
-0.5
-1.0
-1.0
-1.5
-1.5
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
Years
Contd..
Rainfall
R ainfall Anomaly (% of mean)
No clear trend in average annual rainfall over the country
30
30
20
20
10
10
0
0
-10
-10
-20
-20
-30
-30
1870
1880
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
Years
All India summer monsoon rainfall anomalies (1871-1999)
Contd..
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Mathematical Modelling for Prediction of Climate
Change and its Impact on Water Resources
Global Circulation Models (GCM)
Downscaling of GCM Climate Output for use in
Hydrological Modeling on basin/catchment
scale
IMPACT OF CLIMATE CHANGE ON WATER
RESOURCES
Application of Hydrological Models for making
future predictions
Uncertainty Analysis
The Dokriani Glacier (Central Himalayas)
Study Area
Physical Characteristics
8.0
25.0
6.0
Discharge (m 3/s)
• 9.66 km2 (60%) is covered by snow and ice.
Discharge (m3/s)
20.0
• Total drainage area up to the gauging site ~ 16.13km2
1998
Observed runoff
Simulated runoff
Rainfall runoff
Melt runoff
Baseflow
1997
15.0
10.0
4.0
2.0
• Elevation range - 3950-5800 m.
5.0
0.0
0.0
• Length ~ 5.5 km, Width ~ 0.1-2.0 km .
• Maximum glacier area (12.86%) lies in 5000-5100m
range and 12.44% in the 5100-5200m.
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240
240
270
Mon ths
300
330
270
Months
300
Simulation of hydrograph for ablation period of 1997 and 1998
with different components of runoff
330
16
10
1997
T+0
T+1
T+2
T+3
1998
Discharge
Discharge (m3 /s)
8
12
8
4
6
2
The contribution of glacier melt and rainfall in the runoff is 87% and
13%, respectively. For a temperature rise of 2°° C, the increase in
summer stream-flow would be about 28%.
0
0
0
20
40
60
80
Dependability(%)
0
100
20
40
60
80
Dependability(%)
(a)
100
(b)
8
12
1998
1997
P+0%
P-10%
P+10%
6
8
Discharge
Discharge
CONCLUSIONS
4
4
4
• The steeper slope of flow duration curves indicated that
streamflow is fed by direct runoff and there is negligible
amount of storage in the basin.
2
0
0
0
20
40
60
80
Dependability(%)
(c)
100
0
20
40
60
80
Dependability(%)
100
• Also there is marked variability in flows because
of rise in temperature.
(d)
Figure 2 : Flow duration curves of the Dokriani Glacier for
1997 and 1998: baseline and other scenarios.
Chenab Basin Study
Elevation of the study area ~ 305 m to 7500 m.
Mean elevation of the basin ~ 3600 m.s.l.
• The flow currently exceeded 60% of the time (3.2 m3/s in 1998)
would be exceeded 70% of the time under a warming of 2°C.
Total catchment area up to Akhnoor ~ 22,200 km2.
• Temperature has greater influence than rainfall on water
availability
Glacierized Area is 2280 sq km.
Total Number of Glaciers is 989.
• Under different rainfall scenarios - rainfall influences
low flows more in comparison to high flows
8000
T+0oC
T+2oC
Total Streamflow(m3/s)
6000
4000
2000
0
O N D J
F M A M J J
1996/1997
A S O N D J
F
M A M J J A S O N D J F
1997/1998
M A M J J A S
1998/1999
Figure : Effect of increase in temperature by 2oC on daily streamflow for the
years 1996/1997, 1997/1998 and 1998/1999.
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4000
In general, the timing of peak streamflow is not affected;
however, there is a change in the magnitude of peak
streamflow, depending upon the spring melting conditions.
It also indicates that no significant change in the winter
streamflow could be produced for this basin.
For a temperature increase of 2°° C, the variation in annual
streamflow is computed to be 18, 13, 22, 24, 22 and 19%
respectively for 1996/1997, 1997/1998, 1998/1999,
1999/2000, 2000/2001 and 2001/2002.
•
Changes in streamflow for all the seasons are linearly
related to the increase in temperature. The maximum
increase in streamflow is computed to be in pre-monsoon
(snowmelt season).
•
A larger increase in the pre-monsoon season is due to
higher amount of snow/ice melt runoff under a warmer
climate.
T+0 oC
T+2oC
Total Streamflow(m3/s)
3000
2000
1000
0
O N D J F M A M J J
1999/2000
A S O N D J
F M A M J J A S O N D J
2000/2001
F M A M J J A S
2001/2002
Figure : Effect of increase in temperature by 2oC on daily streamflow for the years
1999/2000, 2000/2001 and 2001/2002.
Changes in streamflow (%)
40
1996/1997
1997/1998
1998/1999
1999/2000
2000/2001
30
2001/2002
20
10
0
0.5
1.0
1.5
2.0
2.5
3.0
(a) Increase in air temperature (0 C)
Changes in streamflow (%)
40
Oct - Dec
Jan - Mar
Apr - Jun
Jul - Sep
Annual
30
20
10
0
0.5
1
1.5
2
2.5
3
(b) Increase in air temperature (0C)
Figure : Effect of increase in temperature on annual and seasonal streamflows.
Adaptation issues in water resources sector
The Sutlej River Basin
Hydrological Design Practices
Changes in distribution of melt runoff were more
pronounced during the summer months; a decrease of about
10% runoff for a temperature increase by 2°C, annual
decrease is about 5%.
SW and GW resources assessment (Basin Scale)
Water resources planning
SW and GW resources Development
Mean monthly snowmelt runoff (m 3 /s)
800
T+0 oC
T+2 oC
1996/97
1997/98
1998/99
Operation Policies including real time operations of existing as well as
proposed water resources projects
600
400
Flood and Drought Management (Short term and Long term strategies)
200
Cropping pattern and water demands for irrigation
0
N D J F M A M J J
A S O N D J
F M A M J J A S O N D J F M A M J J A
S O
Effect of increase in temperature on mean monthly snow melt runoff
for a period of 3 years (1996/97-1998/99) in the Sutlej River Basin.
Water Demand Management in different sectors
Water Use efficiency
Groundwater Management in coastal areas
Evacuation and rehabilitation
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CLIMATE CHANGE ISSUES
AND NATIONAL WATER
MISSION
National Water Mission –
objective
Conservation of water, minimizing wastage
and ensuring its more equitable distribution
both across and within States through
integrated water resources management
43
National Water Mission –
identified goals
• Ensure basin level management
• Increase water use efficiency by 20%
• Optimize efficiency of irrigation systems
• Expand irrigation, wherever feasible
National Water Mission –
identified goals (Contd.)
• Meet considerable share of water needs of
urban area through recycling of wastewater
• Adopt desalination techniques for coastal
cities with inadequate alternative source of
water
• Promote water neutral and water positive
technologies
National Water Mission – activities
identified in technical document
• Studies on management of surface water
resources
• Management and regulation of GW resources
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Mission Document –
strategies and action plan
• Reliable assessment of impact of climate
change on water resources
• Basin level planning and management
• Upgrading storage structures for fresh water
and drainage systems for waste water
• Increasing water use efficiency by 20%
• Conservation of wetlands
• Optimize efficiency of irrigation systems
• Development of desalination technologies
• Expand irrigation, where ever feasible
Actions/studies being taken
(MOWR)
Mission Document –
strategies and action plan (Contd.)
• Establishment of Climate Change Cells in CWC,
NIH, BB, CGWB to give impetus to R&D
• Recycling of water
• Promote water neutral and water positive
technologies
• Establishment of Chair Professors in six
academic Institutions viz., IIT, Roorkee,
Kanpur, Guwahati, Kharagpur and NIT,
Srinagar and Patna.
• Other important action points like awareness
programme, review of acceptability/design
criteria etc
• Preparation of report “Preliminary Consolidated
report on Effects of Climate Change on Water
Resources
• Adoption of desalination techniques
NODAL AGENCY: NIH
NIH- NODAL AGENCY
Research area
Strategy 1.5
Research and studies on all aspects related to impact of
climate change on water resources including quality aspects
of water resources with active collaboration of all research
organizations working in the area of climate change
1
Basin efficiency
2
Possibilities of increasing dam heights
3
Identification of minor tanks where FRL can be raised without raising
dam heights by installing gates and evaluation of the same
4
Identification of tanks and water bodies which can be effectively desilted, where silt has commercial value and evaluation of the same
5
Improving intra-national equity in usable water for drought
management like conducting economics considering land, water and
livelihood to plan how much water is necessary to yield reasonable
income
6
Water harvesting, provided this is socially desirable and provided that
corresponding water saving is possible elsewhere in the region
7
Impact on Intensity-Duration-Frequency relationships in urban areas
NODAL AGENCY: NIH
NODAL AGENCY: NIH
Research area
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8
Impact on Magnitude-Duration-Frequency of drought (agricultural,
meteorological and hydrological)
9
Study of Water-energy-Climate Change relationships
10
Planning tidal embankments to protect against tides and increased
flood frequency and increased sea level
11
Effect of sea level rise on ground water salinity and prospective
measures like groundwater recharge
12
Possible tidal channels for fresh water storage
13
Preparation of sediment budgets and accounts for each basin
14
Review the interpretation of regime maintenance on Ganga, after
climate change
15
Isotope applications in GW dating and contaminant transport
16
GW basin models for conjunctive use of SW & GW and application of
RS/GIS in GW management
Research area
17
Assessment and strategies for development potential of deeper
aquifers
18
Coastal aquifer management including use of hydraulic barriers for
control of sea water ingress
19
Assessment of feasibility and viability of rainwater harvesting in
existing domestic and commercial buildings
Supporting researchable issues specifically of:
20
Atmospheric Science Groups towards downscaling of GCM or RCM
to basin/project level and also understanding the effect of climate
change on monsoons
21
Supporting water and climate related researches towards studying
the sensitivity of different hydrologic types of water projects to
different climate change scenarios and improvements required in
hydrometric networks to incorporate climate change
CONCLUDING REMARKS
NODAL AGENCY: NIH
Research area
22
Building a Universal Soil Loss model depicting erosion and
sediment transport etc. Proving the model based on sediment
flow and reservoir sedimentation data, Actuating the above
model for changed rainfall regime and changed management
practices
23
Developing, through R&D effort, a combined unsteady flow
hydraulics-cum-sediment transport model capable of depicting
river erosion in each flood event. Using the model to test river
management works
24
Water quality modelling for each major river and aquifer, and
25
Hydro chemical and solute transport modelling in areas
vulnerable for seawater ingress and water quality problems.
Better observational data and data access
The development of indicators of climate change impacts on
freshwater, and operational systems to monitor them
There remains a scale mismatch between the large-scale climatic
models and the catchment scale
Impact studies of climate change at the monthly or higher temporal
resolution scale is desirable rather than only on annual scale
The impact of climate change on snow, ice and frozen ground
considering non-linear and physically- and process-based hydrological
models coupled with the downscaled output of atmospheric models.
Contd…
CONCLUDING …
Develop local scale data sets and simple climate-linked computerized
watershed models.
Climate change impacts on water quality are poorly understood.
Groundwater has received little attention in climate change impact
assessment compared to surface water resources.
Adaptation processes and methods which can be usefully implemented in
the absence of accurate projections, such as improved water-use
efficiency and water-demand management, offer no-regrets options to
cope with climate change.
An integrated approach is needed, given the diversity of interests to arrive
at sustainable solutions.
R&D studies are needed for the identified thrust Areas under National
Water Mission to achieve the envisaged objectives and goals.
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Gandhi was once asked if he expected India to attain the same standard
Be
the change
of living
as Britain.
He replied:you want to see in the world
It took Britain half the resources of the planet to achieve this prosperity.
How many planets will a country like India require!