Assessing the Viability of Desalination for Rural Water Supply: A Case Study of Chwaka, Zanzibar
Yu, Roy, Packard, Daniele, Cross - Cultural Communication
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
Essential to animal life, water is arguably the most important natural resource people need and the amount of energy and capital used to harvest this resource testify to its importance. The General Assembly of the UN Human Rights Council has established access to safe drinking water as a basic human right and the UN has named 2005-2015 the Water for Life decade, pushing governments worldwide to actively invest in effective water supply (Slade et al., 2012). This study was born from an understanding of the increasing issues with rural water supply in Zanzibar and the emergence of desalination as an alternative source of freshwater to local coastal dwellers. Water scarcity in Zanzibar has been the focus of various previous projects, both Government supported and driven by NGOs. These projects were researched in order to gain a fundamental understanding of both the current and historical perspective on water distribution. As preliminary research indicated, desalination is predominantly located within large hotel resorts in Zanzibar and there are few known examples of machines installed for rural communities. This project sought to investigate the viability of desalination for Chwaka, where foreign investors recently installed a desalination pilot project specifically for local villagers.
Background on Coastal Freshwater Scarcity in Zanzibar
Like island communities all over the world, Zanzibar is almost entirely dependent on groundwater for its freshwater needs due to the absence of rivers or lakes big enough to supply adequate amounts of water (Hans son, 2010). Zanzibar's water supply consists of underground aquifers made up of freshwater lenses floating on a deeper layer of seawater, which are susceptible to disruptions in salt-fresh water balance and permanent saltwater contamination due to overuse and misuse (HALCROW Consulting Engineers, 1994). Recharge of this underground water supply relies entirely on rainfall, which is about 1500-1600 mm annually in Zanzibar, and research has shown that the underground aquifers lose water in the form of runoff into the ocean (HALCROW Consulting Engineers, 1994).
Though Zanzibar receives reasonably adequate rainfall, there are several phenomena that have been making water scarcity an increasingly pressing issue. …