Potential of rainwater harvesting in urban Zambia Lubinga Handia a, * , James Madalitso Tembo a , Caroline Mwiindwa b a Department of Civil and Environmental Engineering, School of Engineering, University of Zambia, P.O. Box 32379, Lusaka, Zambia b SCOPE-OVC, Care International, P.O. Box 36238, Lusaka, Zambia Abstract This paper was associated with a WARFSA funded research project ‘‘Potential of rainwater harvesting in urban Zambia’’. The general objective of the research was to investigate the applicability of rainwater harvesting in urban Zambia. This paper presents the results obtained at the time of writing the paper. Rainwater harvesting was not new to Zambia and there had been installations which were mainly confined to rural areas. Laboratory analysis of water samples from one such system showed that the water was suitable for drinking purposes. Two peri-urban areas of Lusaka were selected mainly based on the water stress in the areas. The socio-cultural survey conducted in the two areas indicated that water ranked among the top two priorities by the Residential Development Committee. Design of the systems was based on the mass curve analysis for storage and rational formula for the gutters. However, a maximum storage of 10 cubic meters was chosen due to budgetary limitation. Construction of five systems was in progress. Ó 2003 Elsevier Ltd. All rights reserved. Keywords: Rainwater harvesting; Water demand; Drainage networks 1. Background According to the ‘‘Social sector rehabilitation and development programme, 1993–1996’’, only 43% of the urban population of Zambia had access to safe water and sanitation structures. The situation in Lusaka was similar to most other cities and towns in the whole country and about one-fifth of the country’s population lived in the city. Therefore, Lusaka was used as an ex- ample of water and sanitation. Estimates by the JICA study team showed that the safe water coverage in Lu- saka was 57% in 1995. Estimates in 2002 for the service level in Lusaka was 80%. The current supply to the city fell short of demand. It had been projected that at the 2002 supply of 200,000 m 3 /day, the city would have deficits of 302,100 and 522,300 m 3 /day in 2005 and 2015, respectively (Yachiyo Engineering Co. Ltd., 1995). The factors that had led to the lack of safe water to the majority of city dwellers were lack of financial re- sources to increase the water supply system and rural to urban migration. Others were lack of services (water and sanitation) to certain areas, inability to pay water bills due to high poverty levels and insufficient knowledge about health. Possible solutions to this problem were to manage the water demand, expand the current supply from Kafue River, increase exploitation of groundwater and start rainwater harvesting. Rainwater harvesting (RWH) is an option which has been adopted in many parts of the world where con- ventional water supply systems have failed to meet the needs of the people. Rainwater collection and utilisation schemes are said to be optimal when implemented in conjunction with water demand management, as well as measures to enhance aquifer recharge (Session reports, 1999). Lusaka Water and Sewerage Company (LWSC) had started a water demand management project con- centrating at reducing leakage, installation of meters, etc. The city’s poor drainage network had made residents believe rainwater was a nuisance as it could not be quickly disposed of through the system. Rainwater had been ignored as a resource. But the piped water con- sumed in the city during one year which was about 73 million cubic meters was exceeded by the 306 million cubic meters of rain that fell over the city. This rain should be harnessed and used. Reclaiming the city’s rainwater as a resource, and the importance of securing water by changing from ‘‘off-site’’ to ‘‘on-site’’ sources is a significant exercise (Murase, 1999). * Corresponding author. E-mail address: handia@eng.unza.zm (L. Handia). 1474-7065/$ - see front matter Ó 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.pce.2003.08.016 Physics and Chemistry of the Earth 28 (2003) 893–896 www.elsevier.com/locate/pce