Sampling Procedure

In order to describe the practices of residents of the Ziway-Shala basin with regards to the water quality, climate change, and socio-economic characteristics, a random sample of 20 villages will be surveyed at the household level and health evaluations will be conducted with two adults, two children ages 10-15, and two children under five years. Eleven of the villages were randomly selected from a stratified list of villages previously sampled for water quality, selecting based on level of fluoride contamination relative to the overall principal component analysis score. The additional 9 villages will be selected from a randomized list of all villages in the Ziway-Shala Basin. Following the randomized order of the list, villages will be accepted for conclusion if they have a functioning groundwater scheme and are accessible from the paved highway for a day trip using a normal four wheel drive vehicle in the dry season. These criteria and this ordered list can be used for additional site selection.

Within each village households will be selected using a modified ‘right-hand rule.’ Given the relatively low density of houses, and the lack of linear housing arrangements, sampling will start at the water scheme (well), and of the three closest houses, one will be randomly selected. From there, every third closest house to the right of the previous sample will be selected, proceeding in a clockwise spiral fashion from the water scheme. If a selected resident declines to participate, either of the next two closest neighbors will be randomly selected to be asked to participate. However, counting will continue from the original selection.