Rainwater harvesting (RWH): a supplement to domestic water supply in Mvog-Betsi, Yaoundé-Cameroon

Andrew Ako Ako,Coretta T Nzali,Lydia Likowo Lifongo,George Elambo Nkeng

doi:10.2166/ws.2021.207

Andrew Ako Ako, Coretta T Nzali + Show 2 more

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https://doi.org/10.2166/ws.2021.207

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Abstract

Abstract This research is aimed at assessing the possibility of using a rainwater harvesting (RWH) system to supplement domestic water supply in the Mvog-Betsi neighbourhood of Yaoundé. The research made use of a 63-year long data series on the amount of rainfall available in the study area, an analysis of rainwater quality and an estimate of the population's monthly water demand in relation to the monthly harvestable rainwater supply. Rainwater supply for the months of September, October and November is 53.05 m3 which is considerably greater than the households' water demand of 25.56 m3 during the long dry season. This led to the design of a 27 m3 ferrocement tank as minimum storage requirement. Furthermore, a rainwater quality analysis showed that all tested parameters conform to water quality standards except for microbiological quality. The rainwater needs to be disinfected before consumption as potable water. Finally, cost estimates for installing RWH systems for low ($419), medium ($549) and high standard ($668) habitations were calculated. RWH can effectively serve as a water supply supplement in the Mvog-Betsi neighbourhood.

Highlights

Rainwater harvesting (RWH), is defined as the collection of water from surfaces on which rain falls, and subsequent storage of this water for later use (Sustainable Earth Technologies 1999)
A little exception is seen in the level of the Potassium (Kþ) ion in which concentration is greater than that of the Cameroon potable water standard
There is a potential public health risk associated with using untreated rainwater as potable water due to microbiological contamination

Summary

Introduction

Rainwater harvesting (RWH), is defined as the collection of water from surfaces on which rain falls, and subsequent storage of this water for later use (Sustainable Earth Technologies 1999). Researchers employ a wide variety of terms and definitions to describe the various methods aimed at using, collecting and storing rain runoff in order to increase the availability of water mainly for domestic and agricultural uses in arid and semi-arid areas (Haut et al 2015). Yannopoulos et al (2016) defined rainwater harvesting as an umbrella term for a range of methods of concentrating and storing rainwater runoff, including from roofs (rooftop harvesting), the ground (runoff harvesting) and from channelflow (flood water harvesting), from various sources (rain or dew) and for various purposes (agricultural, livestock, domestic water supply, environmental management). Decentralized multi-purpose rainwater harvesting systems should be useful infrastructure to mitigate waterrelated disasters such as flooding, sudden water break and fire events, especially in highly developed urban areas in the future. A cost-effective and environmentally friendly solution to flood risks due to urbanisation is the harvesting and reuse of stormwater runoff, in general, and from roofs (Pazwash 2016)

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