深刻な水不足下における家庭レベルでの複合的対策：ネパール国カトマンズ市における事例

Abstract

Water scarcity is a fundamental challenge in many countries. Governmental efforts to address it are often insufficient, making it necessary that adequate household-level coping measures are taken. Using the Kathmandu Valley as a case study, we investigated household coping measures and factors influencing the selection of these measures. Further, we quantitatively estimated the potential amount for gray water use and rainwater harvesting as coping measures in the Kathmandu Valley. Interviews were conducted with 217 households on their water sources/uses and socioeconomic characteristics; 32 households were selected for a survey on the details of water consumption for different purposes using the diary method. Households with shorter periods of piped water supply tended to have a larger number of water supply sources to cope with water shortages. Household income was found to be a major factor influencing the selection of coping measures. The average water consumption was 36.9 ± 11.1 L/cap/day. To cope with water scarcity, the low-income group reduced their water consumption for bathing and laundry while maintaining their consumption for more essential activities such as hygiene and cooking. The study suggested that a 10,000-L water-storage tank for rainwater harvesting would be sufficient to meet the minimum requirement (50 L/cap/day) over a year if gray water use could be practiced in addition to piped water supply.