Ceramic water filters: Red Cross and Red Crescent experiences and lessons in Asia

Ceramic water filters are a low-cost, effective, simple and easily maintained method for water treatment at a household level (or “point of use”) – enabling families to access safe drinking water, free from disease-causing pathogens. Their use across the Asia Pacific region, particularly in South-East Asian countries, is already widespread and continues to grow in popularity. This document captures key experiences from National Red Cross and Red Crescent Societies in Asia who have experience with the production of ceramic water filters, their use in emergencies and/or in the distribution of ceramic water filters as part of ongoing community based development programmes. Key lessons and recommendations for ceramic water filter distribution and programming are outlined, and are relevant for both emergency and longer term development contexts

Mapeamento de reservas de águas subterrâneas no noroeste do Camboja com uso combinado de dados litológicos e sondagens eletromagnéticas de domínio de tempo e por ressonância magnética

International audienceLack of access to water is the primary constraint to development in rural areas of northwestern Cambodia. Communities lack water for both domestic and irrigation purposes. To provide access to drinking water, governmental and aid agencies have focused on drilling shallow boreholes but they have not had a clear understanding of groundwater potential. The goal of this study has been to improve hydrogeological knowledge of two districts in Oddar Meanchey Province by analyzing borehole lithologs and geophysical data sets. The comparison of 55 time-domain electromagnetic (TEM) soundings and lithologs, as well as 66 magnetic-resonance soundings (MRS) with TEM soundings, allows a better understanding of the links between geology, electrical resistivity and hydrogeological parameters such as the specific yield (Sy) derived from MRS. The main findings are that water inflow and Sy are more related to electrical resistivity and elevation than to the litholog description. Indeed, conductive media are associated with a null value of Sy, whereas resistive rocks at low elevation are always linked to strictly positive Sy. A new methodology was developed to create maps of groundwater reserves based on 612 TEM soundings and the observed relationship between resistivity and Sy. TEM soundings were inverted using a quasi-3D modeling approach called ‘spatially constrained inversion’. Such maps will, no doubt, be very useful for borehole siting and in the economic development of the province because they clearly distinguish areas of high groundwater-reserves potential from areas that lack reserves

Assessment of water resources to support the development of irrigation in northwest Cambodia: a water budget approach

International audienceWater availability is the primary constraint on the improvement of food security in rural areas in northwestern Cambodia. A 4-year study was carried out in the upper Stung Sreng watershed to assess water resources. Four sub-watersheds with different land cover types, ranging in size from 1.5 to 185 km2, were monitored using dedicated weather stations and rain- and streamgauges. Geophysics and observation boreholes were used to characterize aquifers. Rainwater is mostly split into evapotranspiration (annual mean of 54% rainfall) and streamflow components (49%), because groundwater recharge is low (1%). Thus, rainwater and streamflow are the main sources for irrigation development. Groundwater can be used only in specific locations for low water-demand crops. A total of 186 household ponds and three village-scale dams were built and 31 wells were installed. The household pond was determined to be the best solution for irrigation development because of its simple management