Indoor resting Anopheles subpictus in a new irrigation scheme in Sri Lanka were investigated during 1989-1990 for malaria infection by dissection and ELISA, and human feeding rates by ELISA analysis of blood meals. Indoor resting abundance was 22.3 females per house per 15-min catch in April-June 1989, 2.2 in November-December 1989, and 7.5 in April-June 1990. ELISA-based malaria infection rates (Plasmodium vivax and P. falciparum combined) were 1.4% during April-June and 3.2% during November-December 1989, and 12.5% during April-June 1990. Dissection and ELISA confirmed the presence of oocysts and sporozoites of P. falciparum in 1990. Human blood was detected in 4.3, 0.8, and 5.2% of analyzed meals, respectively, during the three sampling periods. Estimates of the entomological inoculation rate (EIR) ranged from 0.00006 to 0.005 in different samples and vectorial capacity (VC) was 0.0005 for the 1990 sample. Thus, An. subpictus is incriminated as a vector of human malaria in Sri Lanka.

A 2-yr (1988-1989) survey of mosquitoes breeding in surface water was done in an area of the Mahaweli Project of Sri Lanka that underwent irrigation development and human settlement during the preceding 3 yr. In total, 78,649 immatures of 42 species were collected during the survey. Species of medical importance in the area were Anopheles annularis van der Wulp, An. culicifacies Giles, An. jamesii Theobald, An. nigerrimus Giles, An. subpictus Grassi, An. vagus Doenitz, An. varuna Iyengar, Mansonia annulifera (Theobald), Ma. uniformis (Theobald), Culex fuscocephala Theobald, Cx. gelidus Theobald, Cx. pseudovishnui Colless, Cx. tritaeniorhynchus Giles, and Cx. vishnui Theobald. These and other species used breeding habitats associated with irrigation development (i.e., canals, reservoirs, seepage pools, and rice fields) as well as natural habitats (i.e., rainwater pools, riverbed pools, streams, and marshes). Trends in the use of breeding habitats that were observed with the onset of irrigated rice cultivation in 1987, continued during the period under stable irrigation in 1988 and 1989. Mosquito species richness declined, but species equitability (as indexed by Shannon-Weaver diversity values) did not change. The overall study showed that ecosystem changes concomitant with irrigation development in the Mahaweli Project resulted in long-term changes in the composition of the mosquito fauna, which was characterized by the increasing dominance of species with the potential to transmit human pathogens.

A post-tsunami well recovery support initiative and an assessment of groundwater salinity in three areas of Batticaloa and Ampara Districts Bürgi, ETH, Zürich, Switzerland D.M.D.S. Lionelrathne, IWMI N.G. Indrajith, IWMI S.R.K. Pathirana, WRB 1 Contact E-mail k.villholth@cgiar.org IWMI receives its principal funding from 58 governments, private foundations, and international and regional organizations known as the Consultative Group on International Agricultural Research (CGIAR). Support is also given by the Governments of Ghana, Pakistan, South Africa, Sri Lanka and Thailand. I n t e r n a t i o n a l Water Management I n s t i t u t eAcknowledgements: This project has been funded mainly through CARE International Sri Lanka. The research team appreciates their financial and logistic support. The National Science Foundation of the USA generously granted access to the in-situ probe used for field monitoring of salinity. Mr. Erik Eriksen is acknowledged for his continuous support for the technical aspects of the monitoring.Ms. W.M. Chulani L. Wijethilake, Open University, helped in the digitization of the field data.We want to thank the many local well owners for their patience and collaboration during our recurrent visits to their residences during these times of severe hardship. Officers from government and local authorities, international agencies and NGOs working on the East coast extended their support in numerous ways to the project and we recognize their valuable inputs and cooperation. ............................................................................................................... 62 Appendix A ................................................................................................................. 64 Information on well cleaning ........................................................................................... Executive SummaryThe major tsunami of December 26, 2004 that hit many South Asian countries bordering the Bay of Bengal severely devastated the coastal regions of Sri Lanka. A key concern is the nature and extent of the tsunami impact on the water supply and, in more general, the water resources of these areas. In the coastal areas of Eastern Sri Lanka, the majority of the population, which is rural or semi-urban, is relying on groundwater for their domestic and agricultural activities, most predominantly through traditional private shallow open dug wells in the sandy aquifers. As the tsunami destroyed practically all wells within the reach of the flood waves, access to freshwater for these people was suddenly cut off and interim alternatives had to be sought urgently in the form of freshwater trucked in from unaffected areas.Soon after the tsunami, massive efforts to clean the wells were initiated from a range of different actors in an attempt to rapidly return the water supply to normal conditions, or at least ameliorate the immediate impacts of the salinization of the wells. Based on indications that these efforts were uncoordinated, inadequate, ineff...

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