Rainwater Collection and Storage in Thailand: Design, Practices and Operation

This paper reviews the design of rainwater harvesting systems used for potable water supply in Thailand, its implementation, socio-economic aspects, operation and maintenance, water quality aspects and current practice. Rainwater harvesting has become popular in rural areas of Thailand because of population growth, inaccessibility, contamination and unreliability or unavailability of central water supply. A rainwater harvesting system consists of a collection area, a conveyance system and storage facility. Rainwater storage vessels that are used in Thailand are pots, jars and tanks and are used in combination, for example individual household jars and community oriented tanks. The implementation of the rainwater harvesting program in Thailand is undertaken at several levels: by individual households, by village councils, by external agencies e.g. NGOs and by government. The paper describes this form of implementation. Socio-economic aspects are also discussed. Review of operational aspects revealed neglect of community rainwater jars with intermittent use particularly those in schools and mosquito breeding in rain jars. The quality of stored rain, though unable to meet WHO drinking water standards, is better than most of the traditional water resources in rural areas. Analysis of rainwater jars and tanks revealed that pathogen contamination was slight and can be improved through hygienic collection and handling. A success story of rainwater harvesting from north-east Thailand is reported. NGOs, supported by the Thai government, brought about a dramatic difference to potable water supply for the rural population. Although the Thai case study provides a good example of what is possible, it would be unrealistic to expect other countries to implement either as quickly or as cheaply a nationwide rainwater tank program. The factors that favored the rapid development of rainwater harvesting in Thailand are a need for good quality water, taste and clarity of rainwater, a period of national economic growth and increasing private affluence, the availability of cheap cement, skilled artisans with experience in a similar traditional technology (rain jar), and a pool of indigenous engineers, technicians and administrators committed to rural development programmes.