Assessing construction material costs of constructed rainwater harvesting storage tanks used by households in rural areas of Uganda.

Abstract

Given the growing demand for domestic rainwater harvesting in the developing world visa vie the low adoption rates in rural areas, the constructed domestic rainwater harvesting technologies need to be built with utmost attention to cost. Low cost constructed rainwater storage technologies such as rainwater jars, ferrocement tanks, masonry tanks, need to be explored. This paper assesses the construction material costs of domestic rainwater storage technologies used in rural Uganda to find the most cost-effective option. Material quantities were obtained from bills of quantities for constructed technologies and prices were obtained from hardware shops and construction sites. The materials were then broken down into six material components of cement, other externally sourced materials, locally available materials, equipment and tools, transport, and labour. Masonry brick tanks were found to be the most commonly used constructed domestic rainwater storage technology with a dominance of 50%. However, the above ground mortar jar was found to consume relatively less cement (1.3 bags of cement per cubic metre) and externally sourced materials (mainly reinforcement) compared to a masonry tank (2.1 bags per cubic metre) and the highest percentage of unskilled labour compared to other technology types. Therefore, this study suggests that the above ground mortar jar is the cheapest technology option costing USh. 726 per litre and hence the most cost-effective option of all the identified technology types used in rural Uganda.