Water for a food-secure world
Climate change, water resource development and malaria in
EthiopiaEline Boelee, Matthew McCartney,
Mekonnen Yohannes, Fitsum Hagos, Jonathan Lautze, Solomon Kibret
Presented at “Water and Health: Where Science Meets Policy,”The University of North Carolina at Chapel Hill, USA
October 25-26 2010
Water for a food-secure worldWater for a food-secure world
Key message
Climate change necessitates water storage,
which may increase health risks
that can be mitigated.
Water for a food-secure worldWater for a food-secure world
Malaria in Ethiopia as an example
Koka reservoir
(Source: MoH & WHO 2007)
Water for a food-secure worldWater for a food-secure world
Impacts of climate change
• Increased variability of rain• Reduced availability of water• Reduced water & food security• Need for water resources development• Water storage has a role to play in adaptation to
climate change• Impacts on mosquitoes, parasites, transmission cycle
Water for a food-secure worldWater for a food-secure world
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1950 1970 1990 2010 2030 2050
Year
Pe
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Av
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. m
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Water resources development in Ethiopia
(Source: Awulachew et al. 2005)
• Per capita water availability declining• Water Sector Development Program 2002-2016• River diversion / irrigation systems• Rainwater harvesting ponds• Large multipurpose dams• Small reservoirs• DWSS*
Photo C
redit: Eline B
oelee
*DWSS: Drinking Water Supply and Sanitation
Water for a food-secure worldWater for a food-secure world
Water storage• Focus on water for agriculture, incl. livestock • Integrated into most water systems• Save water over time for access at critical periods• Diverted from rivers, rainwater harvesting, aquifers• High variety
– Tanks, reservoirs– Groundwater– Large / small– Open / closed– Man-made / natural
Photo Credit: Eline Boelee
Water for a food-secure worldWater for a food-secure world
Water storage continuum
(Source: McCartney & Smakhtin 2010)
Water for a food-secure worldWater for a food-secure world
Reduced climate vulnerability
pre-adaptation
Future climate vulnerability < present climate vulnerability
Present climate vulnerability
Increased availability and access to water
Increased adaptive capacity
Increased agricultural productivity
Increased water security
post-adaptation
adaptation strategy
Future climate vulnerability
Water storage
(Source: Adapted from McCartney & Smakhtin 2010)
Water for a food-secure worldWater for a food-secure world
Health risks of open water
• Expanded water surface for longer periods• Drowning, water quality, vector-borne diseases• Increased malaria transmission associated with
– Small reservoirs < 100 – Surface irrigation (estates & small-scale)– Rainwater harvesting ponds > 100,000– Increasingly higher altitudes
• Current control strategies insufficient– Bednets, house spraying– Shift in biting rhythm– Foreign currency, resistance
Water for a food-secure worldWater for a food-secure world
Malaria at Koka Lake, Rift Valley
• Increased transmission near lake• Decision support for dam operation• Potential for larval control by dam operation
(water level fluctuation)
Photo Credit: Solomon Kibret
Water for a food-secure worldWater for a food-secure world
y = -27.51ln(x) + 62.462R² = 0.9149
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Distance f rom the reservoir (km)
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Observed Predicted Water level change
Koka• Malaria cases
correlate with– Distance from
reservoirs– Water level
fluctuations (Source: Kibret et al. 2009)
(Source: Lautze 2008)
Water for a food-secure worldWater for a food-secure world
0.00
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Feb-0
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-07
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-06
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An. arabiensis (Reservoir villages)
An. pharoensis (Reservoir villages)
An. arabiensis (Control villages)
An. pharoensis (Control village)
Koka• Adult Anopheles more abundant closer to reservoir• More breeding sites near shore line, mainly in hoof prints
(Source: Lautze 2008)
Water for a food-secure worldWater for a food-secure world
Koka• Reservoir crucial for livestock watering
Photo C
redit: Matthew
McC
artney
Water for a food-secure worldWater for a food-secure world
y = 3.7002x + 105.48R² = 0.4383
-20
0
20
40
60
80
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120
-35 -30 -25 -20 -15 -10 -5 0
Tota
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Rate of falling water levels (mmd -1)
Koka• Anopheles larval abundance related to drawdown rate• Can malaria control be incorporated into dam
management?
(Source: Kibret et al. 2009)
Water for a food-secure worldWater for a food-secure world
Small reservoirs, Tigray
• Mosquito breeding in seepage areas• Increased transmission, year round,
near micro-dams• Limited impact on agricultural
productivity
Photo Credit: Eline Boelee
Photo Credit: Eline Boelee
Water for a food-secure worldWater for a food-secure world
Water harvesting ponds
• Even tiny plots require labor at critical times
Ph
oto
Cred
it: Elin
e Bo
elee
Water for a food-secure worldWater for a food-secure world
Water harvesting ponds• Significantly more malaria near ponds • Determinants of malaria
– House type – Distance to wells– Toilets– Bed net– Season
0
10
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50
60
High landponds
High landcontrol
Mid Landponds
Mid Landcontrol
Low landponds
Low landcontrol
Mal
ari
a p
rev
ale
nce
(%
)
Nov. 2004
Dec. 2004
Mar. 2005
May. 2005
Pho
to C
red
it: Elin
e B
oe
lee
Pho
to C
red
it: Martine Jeths
Photo Credit:
Source: graph created by E.Boelee for this presentation based on Hagos et al. 2006
Water for a food-secure worldWater for a food-secure world
Shift in biting rhythm
• Main vector Anopheles arabiensis
• Peak in biting activity after midnight
• Change to early evening
Rift Valley
(Source: Kibret et al. 2010)
Water for a food-secure worldWater for a food-secure world
Reduced climate vulnerability
pre-adaptation
Present climate vulnerability
Increased availability and access to water
Increased adaptive capacity
Increased agricultural productivity
Increased water security
post-adaptation
adaptation strategy
Future climate vulnerability
Water storage
Increased malaria
Future climate vulnerability > present climate vulnerability(Source: Adapted from McCartney & Smakhtin 2010)
Water for a food-secure worldWater for a food-secure world
Way forward
• In Ethiopia– No additional small dams– Large hydropower dams <10– Upgrading and expansion of irrigation– Water harvesting: ponds and in situ
• No capacity for mitigating measures• Try to influence policy, planning and design
Photo Credit: Eline Boelee
Water for a food-secure worldWater for a food-secure world
Intervention options• Complementary to early diagnosis and
treatment• Transmission reduction
– Zooprohylaxis?• Source reduction
– Participatory approaches – Engineering / agricultural measures
• Alternative water storage options– Aquifers– Soil moisture– Wetlands
Photo Credit: Michiko Ebato
Water for a food-secure worldWater for a food-secure world
safeWater
storage
Reduced climate vulnerability
pre-adaptation
Present climate vulnerability
Increased availability and access to water
Increased adaptive capacity
Increased agricultural productivity
Increased water security
post-adaptation
adaptation strategy
Future climate vulnerability
Increased malaria
Future climate vulnerability < present climate vulnerability(Source: Adapted from McCartney & Smakhtin 2010)
Water for a food-secure worldWater for a food-secure world
Key message
Climate change necessitates water storage, which may increase health risks
that can be mitigated
Thank you!
Water for a food-secure worldWater for a food-secure world
Related Publications• Kibret, S.; Alemu, Y.; Boelee, Eline; Tekie, H.; Alemu, D.; Petros, B. 2010. The impact of a small-scale
irrigation scheme on malaria transmission in Ziway area, central Ethiopia. Tropical Medicine and International Health, 15(1):41-50
• McCartney, Matthew; Smakhtin, Vladimir. 2010. Water storage in an era of climate change: addressing the challenge of increasing rainfall variability. Blue paper. Colombo, Sri Lanka: International Water Management Institute (IWMI). 14p.
• Kibret, S.; McCartney, Matthew; Lautze, Jonathan; Jayasinghe, G. 2009. Malaria transmission in the vicinity of impounded water: evidence from the Koka Reservoir, Ethiopia. Colombo, Sri Lanka: International Water Management Institute (IWMI). 39p. (IWMI Research Report 132)
• Kibret, Solomon; McCartney, Matthew; Lautze, J. 2008. Mosquitoes and malaria in the vicinity of the Koka Reservoir, Ethiopia. In Humphreys, E.; Bayot, R. S.; van Brakel, M.; Gichuki, F.; Svendsen, M.; Wester, P.; Huber-Lee, A.; Cook, S. Douthwaite, B.; Hoanh, Chu Thai; Johnson, N.; Nguyen-Khoa, Sophie; Vidal, A.; MacIntyre, I.; MacIntyre, R. (Eds.). Fighting poverty through sustainable water use: proceedings of the CGIAR Challenge Program on Water and Food, 2nd International Forum on Water and Food, Addis Ababa, Ethiopia, 10-14 November 2008. Vol.1. Keynotes; Cross-cutting topics. Colombo, Sri Lanka: CGIAR Challenge Program on Water and Food. pp.34-37.
More related publications continued on next slide…..
Water for a food-secure worldWater for a food-secure world
Related Publications• Lautze, J. 2008. Incorporating malaria control into reservoir management: a case study from Ethiopia. PhD
thesis, Tufts University, Boston, USA.
• Hagos F, Yohannes M, Linderhof V, Krusemand G, Mulugeta A, G/Samuel G, Abreha Z (2006) Micro water harvesting for climate change mitigation: Trade-offs between health and poverty reduction in Northern Ethiopia. PREM Working Paper 06/05. Poverty Reduction and Environmental Management (PREM), Institute for Environmental Studies. Amsterdam: Vrije Universiteit. http://www.prem-online.org/archive/12/doc/PREM06-05.pdf
• Awulachew, S. B.; Merrey, D. J.; Kamara, A. B.; Van Koppen, B.; Penning de Vries, F.; Boelee,E.; Makombe, G. 2005. Experiences and opportunities for promoting small–scale/micro irrigation and rainwater harvesting for food security in Ethiopia. Colombo, Sri Lanka: IWMI. v. 86p. (Working paper 98)
For further information, please visit: www.iwmi.org