Water-related adaptation to
climate change
Alemseged Tamiru Haile (Ph.D.)
28 January 2014
Water for a food-secure world
Water scarcity
Physical scarcity: Not enough water.
Economic Scarcity: Not infrastructure to make water available to
people
Both scarcities should be managed
Water for a food-secure world
Distribution of the percentage of area under
irrigation
Ample room for development
Irrigated Land (% of Crop Land)
45
40
35
30
25
20
15
10
5
0
South Asia
Middle East &
North Africa
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East Asia &
Pacific
Latin America &
Caribbean
Sub-Saharan
Africa
Climate change: change in the statistical
properties of the climate system
Economy, Population, Technology
Increased GHGE
Fossil fuel, GW pumping, Land
use change, Livestock
Anthropogenic Global warming
Regional Changes
Precipitation, Temperature, sea level
Impact
Water, Agriculture, Energy, etc.
Measures
Mitigation, Coping, Adaptation
Average condition, Variability,
Extremes
Demand, Supply, Reservoir
evaporation, Infrastructure damage
Adapt to (i) less soil moisture and
higher evaporation, (ii) Increased
floods
Loss and damage
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Climate change adds new challenges
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African Scenarios – uncertainty is the keyword!
Changes in surface water supply
across Africa with Predicted
Climate Change
Increases and decreases:
Small changes in temperature will
see average river flows and water
availability increase by 10-40% in
some regions, while in others there
will be a decrease of 10-30%
Example: Blue Nile GCM Downscaling
Precipitation
Potential ET
Source: Maartin de Wit and Jacek Stankiewicz
www.scienceexpress.org/2March2006/Page1/10.1126/science1119929
Actual ET
Runoff
a food-secure
world
10 models showWater
likely for
decrease
of runoff
7 shows like increase of runoff
Climate change: Ethiopia
• Studies show impact of CC on Sectors
• By 2050 climate change could cause [Robinson et al., 2013]:
– GDP to be 8–10 percent smaller than under a no-climate
change baseline;
– a two-fold increase in variability of growth in agriculture;
– it would affect more severely the poor and certain parts of
the country.
• ADAPTATION IS THE PRIORITY
Water for a food-secure world
Barriers to adaptation (Based on Deressa et
al., 2009 and Haile et al., 2014)
• Farmers’ perception is there is
long-term temperature and
precipitation change
• The least practiced adaptation
strategy by HHs in the Nile
basin is - Irrigation
• Barriers to adaptation
– Not knowing which kind of
measures to take
– Insufficient financial means
– Shortage of labor
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Water-related adaptation to climate change
Despite its high productivity, irrigation is under growing
pressure to reduce its environmental impact, including soil
salinization and nitrate contamination of aquifers
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Water-related adaptation to climate change
• Inadequate storage leaves farmers vulnerable to CC
• Store water for use in times of shortage
• Continuum of storage: Reservoirs, Ponds and tanks, aquifer,
soil moisture
• The best option is to focus on
– Combining a variety of storage types
– Consider CC in planning, design and operation
– Types of storage – tailored to specific conditions
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Household Irrigation Technology (HIT) to
transform Ethiopian agriculture sector
• Agricultural intensification - “Save and Grow” - requires
– Target households
– Knowledge-based precision irrigation
– Use of improved, drought tolerant varieties and management practices
that save water
– Reliable and flexible water application
• Deficit irrigation
• Estimates over the next 5 years indicate HIT could enable:
– Over 500,000 ha could be irrigated - Doubling existing irrigation
– >650,000 farming households to become agricultural entrepreneurs,
– increasing family income and food security for almost 5 million
Ethiopians
– Adding $600 million USD and 30,000 jobs to the national economy
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7 major bottlenecks in the Household
Irrigation sector of Ethiopia (Source: ATA)
1.
2.
3.
4.
5.
6.
7.
Lack of readily available information on groundwater resource potential
– to recommend technically feasible water lifting and saving
technologies
Lack of data on high value crops for specific agroecology of the woredas
Absence of well-trained manufacturers to produce quality manual and
mechanized HITs for smallholders, and lack of clear standards for HITs
Lack of reliable and interdependent HITs and other irrigation agriculture
input supply chain
Absence of credit access to smallholder farmers to purchase HITs and
other agriculture inputs during irrigation season
Smallholders are not getting the right training and advisory support on
irrigated agriculture and the agriculture research system offers limited
attention to high value crops
Frequent HIT failures and absence of locally available maintenance
services or spare parts
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Adaptive management of groundwater
(AMGRAF)
• Aim: to enable sustainable development of accessible
(shallow) groundwater for small-scale irrigation
•
•
•
•
Assessment of groundwater resource and use
Development of tools for adaptive groundwater management
Research into scenarios of water management
Socio-economic: Livelihood impact, governance, institutions
• Working definition of ‘accessibility’
– The depth to GW should be less than 30m
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Adaptive management of groundwater
(AMGRAF)
Key findings include (eg):
•
•
•
•
•
There is some experience of GW use
GW resource is not evenly distributed among households
How to break Hard rocks to access water below 10-15 metres?
Overexploitation???
Limitations to expanding use of irrigation include: water lifting
mechanisms; wells dry out, scarcity of land; shortage of seedlings
• If more irrigation available, would grow vegetable crops (onions, cabbage,
pepper, garlic etc)
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Spate irrigation
“Floods are not always a hazard. They may also sustain aquatic life and riverine
biodiversity, recharge aquifers, enrich soils and in some of the world’s poorest areas
they are the main source of irrigation.”
Global Water Partnership (2000) ‘Toward water security: a framework for
action’
• Expansion of Spate Irrigation due to
– Physical reasons
• Lowlands: extensive flat, fertile surrounded by hills with high rainfall
• The expansion of agriculture to the mountains
– land degradation, reduced base flow, increased drought
– Socio-economic reasons
• Increased population in the lowland areas - increased demand
• provides the livelihoods for economically marginal people
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Spate irrigation
• Climatic factor for use of SI:
– Reduced rainfall
– Increased dry spells
– Increased temperature
• Challenges:
– Unpredictable floods
– Frequent damage of structures
• Increased floods
– Encourage SI
Farmers observations over the
last decade
Observation
% of farmers
Rainfall decreased
63
LGP reduced
85
Temperature increased
73
Freq. of dry spells
increased
64
Volume, freq. and
duration of spate flow
decreased
90
How to properly to divert and manage
the flood water for crop production?
Water for a food-secure world
IMPACT2C
• Several reservoirs planned in Blue Nile
– Target ensuring food security at households-E.g. Upper Beles:~20000 HHs
• What is the link between these reservoirs?
– Upstream-downstream trade-offs and opportunities
– Hydropower, irrigation, environment
– Water allocation
• CC impact on
– Demand and supply
• Role of reservoirs - adaptation
– Variability vs supply
– Flood control
– Water allocation
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IMPACT2C
• Quantifying projected impacts under 2°C warming
• Global climate modeling (GCM), dynamic regional
downscaling (RCM), and bias correction
• Set of models and approaches can be used to assess impact
• SWAT, HBV
• WEAP,
• CROPWAT,
Mendlik and Gobiet (2013)
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Conclusion
•
•
•
•
Better communicate CC uncertainty
Adapt to less soil moisture and increased floods
Invest in R&D to enhance adaptation
Accessibility is more important than potential – infrastructure
– RWH (in-situ soil moisture maximization, ponds)
– Shallow GW wells
• Provide more and diverse physical storage infrastructure
• Consider CC in planning, design & operation of storage schemes
• “Save and Grow”
– Irrigation technologies (treadle pumps, hand pumps, drip irrigation) and
water saving
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THANK YOU!!!
Water for a food-secure world