Assessing the Viability of Desalination for Rural Water Supply: A Case Study of Chwaka, Zanzibar

Abstract

Zanzibar has been struggling with water scarcity issues over the last few decades due to an increase in consumption on the island and a deterioration of existing supply infrastructure. Poor distribution has affected rural communities most, due to their absence of tourism development, which has gone hand in hand with infrastructure establishment. Foreign aid has begun to address the issue by investing in alternative forms of water supply. In November 2011, a solar and wind powered desalination unit was inaugurated in the village of Chwaka, which, previous studies have shown, suffers from salt contaminated wells. This study sought to assess the viability of this alternative source of water in Chwaka and found that the desalination unit installed is not a viable source of freshwater for the entire village of Chwaka compared to government piped well water. Installed with the best intentions for the people of Chwaka, the presence and purpose of the machine is unknown to most of the village and its production capacity could only hope to supplement drinking water. Relative investment costs of distributing similar volumes of water show that piped water is the cheaper option. The intentions of the project are nonetheless laudable and this type of innovative investment should be encouraged as long as the government is not asked to take the bill. Zanzibar has access to adequate freshwater resources and must look to efficient consumption before turning to alternative forms of water production.

Key words: Advantages; Alternative; Chwaka; Desalination; Disadvantages; Drinking; Freshwater; Supply; Tanzania; Viability; Water; Zanzibar