Enhancing Water Security: Unlocking the Potential of Rainwater Harvesting in Zanzibar

Water scarcity is a critical concern for Zanzibar, driven by rapid population growth, urbanization, and the impacts of climate change. As freshwater resources dwindle and groundwater becomes increasingly vulnerable to overexploitation and saltwater intrusion, exploring alternative sources has become imperative. Rainwater harvesting (RWH) presents a promising, low-energy solution: by capturing rainfall that would otherwise run off, communities can reduce stress on aquifers and improve resilience against droughts and sea-level rise.

Why Rainwater Harvesting Matters
Despite high rainfall levels, much of Zanzibar’s precipitation is lost to surface runoff. Learning from Pacific and Caribbean island nations—where over 90% of households rely on RWH—this study highlights the untapped potential of rooftop and community-level systems in Unguja and Pemba. By integrating RWH, local stakeholders can buffer against erratic rainfall patterns, reduce dependence on mismanaged piped supplies, and align with Zanzibar’s Vision 2050 goals for sustainable water and sanitation services.

Key Objectives of the Study

1. Assess Existing Systems: Through field surveys and stakeholder interviews, the research will evaluate the capacity, efficiency, and affordability of current RWH installations.
2. Evaluate Legal Frameworks: A policy review and consultations will identify gaps in regulations and institutional support for RWH adoption.
3. Map Potential Sites: Using geospatial tools (e.g., GIS) and on-the-ground validation, the team will pinpoint high-potential locations for new RWH interventions.
4. Understand Community Perceptions: Surveys and focus groups will capture local attitudes, traditional knowledge, and barriers to RWH uptake—ensuring recommendations are culturally appropriate.

Study Approach
Led by the Ministry of Water, Energy and Minerals (MoWEM) in partnership with Global Water Partnership Tanzania (GWPTZ) and supported by UONGOZI Institute, the research combines primary and secondary data collection. Digital tools like Kobo Toolbox will streamline surveys, while stakeholder workshops will foster collaboration among government agencies, NGOs, and community leaders. By focusing on both technical performance and social acceptance, the study aims to create a holistic picture of RWH feasibility across Zanzibar.

What to Expect

• Performance Report: A detailed analysis of how existing RWH systems are functioning, including cost-effectiveness and sustainability insights.
• Policy Recommendations: Actionable guidance for improving regulatory frameworks, clarifying stakeholder roles, and incentivizing RWH investment.
• Site Maps and Action Plans: Geospatially informed maps highlighting priority areas for RWH, complete with estimated costs and implementation timelines.
• Community Insights: Documentation of local knowledge, preferences, and cultural considerations to ensure RWH solutions are both effective and embraced by residents.

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