Climate change, water resource development and malaria in ethiopia

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.


Malaria in Ethiopia as an example

Koka reservoir

(Source: MoH & WHO 2007)


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


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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 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 storage continuum

(Source: McCartney & Smakhtin 2010)


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)


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


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


y = -27.51ln(x) + 62.462R² = 0.9149

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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)


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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)


Koka• Reservoir crucial for livestock watering

Photo C

redit: Matthew

McC

artney


y = 3.7002x + 105.48R² = 0.4383

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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)


Small reservoirs, Tigray

• Mosquito breeding in seepage areas• Increased transmission, year round,

near micro-dams• Limited impact on agricultural

productivity




Water harvesting ponds

• Even tiny plots require labor at critical times

Ph

oto

Cred

it: Elin

e Bo

elee


Water harvesting ponds• Significantly more malaria near ponds • Determinants of malaria

– House type – Distance to wells– Toilets– Bed net– Season

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it: Elin

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Pho

to C

red

it: Martine Jeths

Photo Credit:

Source: graph created by E.Boelee for this presentation based on Hagos et al. 2006


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)



pre-adaptation






post-adaptation

adaptation strategy


Water storage

Increased malaria

Future climate vulnerability > present climate vulnerability(Source: Adapted from McCartney & Smakhtin 2010)


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



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


safeWater

storage


pre-adaptation






post-adaptation

adaptation strategy


Increased malaria

Future climate vulnerability < present climate vulnerability(Source: Adapted from McCartney & Smakhtin 2010)


Key message

Climate change necessitates water storage, which may increase health risks

that can be mitigated

Thank you!


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…..

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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

Climate change, water resource development and malaria in ethiopia

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