VOL. 8, NO. 1, JANUARY 2013 ISSN 1819-6608 ARPN Journal of Engineering and Applied Sciences © 2006-2013 Asian Research Publishing Network (ARPN). All rights reserved. www.arpnjournals.com 1 EXAMINING THE EFFECTIVENESS OF RAINWATER COLLECTION SYSTEMS IN A NIGERIAN LEPER COLONY USING THE BEHAVIOURAL MODEL Olaoye Rebecca A. 1 , Coker Akinwale O. 1 , Sridhar Mynepalli K. 1 and Adewole Esan M. 2 1 Department of Civil Engineering, Faculty of Engineering, University of Ibadan, Oyo State, Nigeria 2 Department of Civil Engineering, Faculty of Engineering and Technology, Ladoke Akintola University of Technology, Ogbomoso, Nigeria E-mail: radeshiyan@yahoo.com , ABSTRACT Rainwater from roof catchments can be a valuable source of water and can be quite safe to drink when stored in a properly installed and well maintained water storage system. It is noteworthy to observe the capacity intended for rainwater storage because this factor is a determinant to both its initial cost of construction and its effectiveness, especially during the dry season for the isolated lepers who are sited outskirts of towns and cities where the water mains does not get to. This paper examines the effectiveness of rainwater collection systems in a Nigerian leper colony using behavioral method, such that the relationship between the storage and the utility or demand was punctuated in terms of water saving efficiency. The data obtained were used to mathematically simulate the model algorithms using the time interval of an hour, a day and a month. The detailed analysis for the application of these time interval models were expressed in a dimensionless ratio known as the storage fraction, S/AR, where S = storage capacity (m³), A = roof area (m²), and R = average annual rainfall (m). The values obtained for the water saving efficiency using the YAS and the YBS algorithms shows that the YBS gives an exaggerated value for the data plots while the YAS operating algorithm showed a conservative estimate and could be use as a standard of comparison and calibration for other models. The hourly models can therefore be most effective for relatively small stores with storage fractions less than 0.014. Daily models can be used more effectively for stores with storage factions above 0.014 while the monthly time model for store capacities with storage fractions greater than 0.13. Keywords: Rainwater harvesting, collection systems, roof catchment, water saving efficiency, sustainable water source. List of symbols R Average annual rainfall (m) Yt Yield (m³) Dt Demand (m³) Vt Volume of rainwater (m³) Vt-1 Volume of water in tank from the time interval t–1(m³) Qt Runoff into tank (m³) S Capacity of the tank/ storage capacity (m³) A Roof area (m²) D Annual demand (m³/yr) ET Water saving efficiency at time t YAS Yield after spillage YBS Yield before spillage t Time interval (hour, day, month) 1. INTRODUCTION A safe and potable water is yearned for globally, one which can be easily harnessed when needed but nevertheless this necessity has proved somewhat difficult for the government and the non-governmental organisations who from day to day strife to meet the daily requirements of the masses. Many lepers communities all over the world are approaching the limits of their traditional water resources as thousands of lepers throughout the world still do not have access to adequate water a basic necessity for well being and development. The situation is even direr in developing country like Nigeria [1, 2, 3, and 4] where even the towns and cities lack adequate water supply [5, 6]. On the other hand, rainwater harvesting has drawn increased attention in many parts of the world as an economic and sustainable water source both for potable and non-potable use [7]. Hence the collection of rainwater from roof catchments and storage is a viable method of reducing water scarcity in leper colonies all over the world. As a general rule, rainfall should be over 50 mm/month for at least half a year or 300 mm/year to make Rain Water Harvesting environmentally feasible [8]. Without extensive treatment required rainwater can be suitable for a range of household chore such as drinking, WC flushing, clothes washing, garden irrrigation, and in some cases bathing. Rainwater harvesting has maintained its importance as water source for small scale agriculture and as a primary water source in the remote locations in the rural areas and islands, so this could be applicable for the lepers who are sited outskirts of cities where the water mains are inaccessible [9, 10]. Rainwater harvesting has become a popular supplement for potable water to reduce the demand on the conventional water supplies even in the cities where the surface water is polluted or the groundwater is over extracted due to rapid increase in population. The cost of rainwater collection tend to be quite small but the largest economic consideration is the initial capital cost to construct the collection system. In lepers’ colony, rural areas and even in some urban households where rainwater is valued it could be harnessed with bowls, buckets, jerry cans, tanks etc. But in the case where there is need to utilize this natural water source maximally, the