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Methodology for vector breeding:
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To determine the links between irrigation and malaria transmission, several
methods were combined.
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A malaria risk map was produced by combining malaria cases and environmental
parameters such as amount of irrigation, presence of other surface water
bodies, soil moisture, land use patterns, and vegetation cover, all in one GIS,
based on existing maps and databases (Uda Walawe is one of IWMI's benchmark
basins) and high-resolution satellite images.
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Complementary data were collected in the field using standard entomological
protocols for spray catches, cattle traps, and larval sampling.
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Additional socio-economic information was obtained through questionnaires.
Feedback was obtained during workshops, which led to additional studies.
Methodology water for domestic use:
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For this component several sub-studies were carried out at different scales.
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One study assessed the impact of concrete lining of irrigation to reduce
seepage losses on water availability for domestic purposes. Groundwater levels
were measured in piezometers and wells, while surface water was measured in
canals and on rice fields. At the same time, biological water quality was
assessed by determining concentrations of fecal coliform bacteria and
Cryptosporidium and Giardia parasites in the field laboratory.
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A parallel study on chemical water quality used special probes combined with
isotope analyses and led to a geohydrological map and a vulnerability analysis
for fluoride. This was complemented by a dental survey among school children to
determine the prevalence of dental fluorosis.
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To predict the downstream impacts of a newly planned extension of the
irrigation system, surface and groundwater flows were measured in the extension
area. With these data a simulation model was developed in which the new design
flows could be entered.
Methodology for pesticides:
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After a review of literature and local unpublished laws and guidelines, field
studies were carried out. These involved inventories of current pesticide use
and availability in shops, as well as a biomedical survey, which involved
questionnaires, repeated blood sampling to measure acetylcholinesterase
activity, and detailed neurological studies.
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Pesticide use and symptoms were compared among 242 farmers, 131 of which
applied integrated pest management, and 55 fishermen. To disseminate the
findings from the studies on pesticides, a national workshop was organized in
Colombo to share the research results with stakeholders and to provide a forum
for dissemination of knowledge on the use and risks of pesticides in Sri Lanka.
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