Assessment of rainfall variability, rainwater harvesting potential and storage requirements in Odeda Local Government Area of Ogun State in South-western Nigeria

Isaac Idowu Balogun,Adebayo Olatunbosun Sojobi,Bosede Oyegbemijo Oyedepo,Serge Wich

doi:10.1080/23311843.2016.1138597

Isaac Idowu Balogun, Adebayo Olatunbosun Sojobi + Show 2 more

Open Access

https://doi.org/10.1080/23311843.2016.1138597

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Abstract

AbstractRainfall variability with periodicity of 5–6 years has been demonstrated for our study area and may be attributed to tropical and extra-tropical factors which operate during different months, seasons and years. Rainfall variability in terms of coefficient of variation ranges from 24 to 39% and 26 to 41% for the seasons and months. The mean increase of 1.63 mm/year and 1.37 mm/year experienced in the dry season months (November–April) and the wet season months (May–October), respectively, is insignificant from a water management perspective. Hoeffding’s D statistics revealed prevalence of non-monotonic trend in all the months and seasons. Recommended minimum and maximum storage capacity requirements for a six-member household to maximize rainwater harvesting are 1 and 6 m3, respectively. The rainwater harvesting potential for the area of study ranges between 18.16 and 27.45 m3 and 15.23 and 30.40 m3 based on the maximum error estimate and coefficient of variation methods. Domestic rainwater harvest...

Highlights

Sustainable access to water for potable and non-potable uses continues to pose a huge challenge in developing countries
Based on Hare’s (1983) rainfall variability index, rainfall in Summer and Spring were highly variable with index > 30%, while rainfalls in Winter and Autumn were moderately variable with index between 20-30%
Rainfall variability has been demonstrated for our study area and it may be attributed to tropical and extratropical factors which operate during different months, seasons and years

Summary

Introduction

Sustainable access to water for potable and non-potable uses continues to pose a huge challenge in developing countries. Sub-Saharan Africa (SSA) alone accounts for 40% of the global population without access to safe drinking water (Sojobi, Owamah & Dahunsi, 2014). In Africa, it was estimated that 75-250 million people would be exposed to increased water stress by 2020 (Kalungu et al, 2014). This worrisome situation is further aggravated by poor water governance, extreme social inequality, population growth and climate change in Africa. Rainwater harvesting (RWH) has been proposed as one of the options to improve water supply especially in rural and peri-urban areas of low-income countries (Opare, 2012; Cruddas et al, 2013), areas without reticulated water supply (Ndiritu, Odiyo, Makungo, Ntuli & Mwaka, 2011), water-scarce, remote and marginalized areas (Nijhof, Jantowski, Meerman & Schoemaker, 2010), areas where existing water supply is inadequate (Aladenola and Adeboye, 2010), areas with abundant annual rainfall (Ghisi & Schondermark, 2013), highly contaminated and saline coastal areas (Samaddar, Murase & Okada, 2014) as well as arid and semi-arid regions (Branco, Suassuna, Vainsencher, 2005; Abdulla & Al-Shareef, 2009)

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