Design and evaluation of a solar-powered rainwater harvesting system in urban areas

Thesis Abstract

Urban areas face increasing water scarcity exacerbated by climate variability, unsustainable water management practices, and growing population demands. Rainwater harvesting offers a sustainable alternative to augment potable water supplies, yet conventional systems often lack renewable energy integration, limiting efficiency and autonomy. This research aims to design, implement, and evaluate a solar-powered rainwater harvesting system tailored for dense urban environments, with the goal of enhancing water security and promoting sustainable urban water management. The specific objectives are to develop a comprehensive design model integrating photovoltaic (PV) systems with rainwater collection infrastructure, assess the technical feasibility and efficiency of the integrated system under varying climatic conditions, and evaluate the socio-economic and environmental impacts of deploying such systems in urban neighborhoods. The study adopts a mixed-methods research design, combining quantitative technical assessments with qualitative stakeholder analyses. The research population comprises urban households, municipal water authorities, and renewable energy professionals within a metropolitan city with an estimated population of 3 million residents. A statistically determined sample size of 150 households will be selected through stratified random sampling to ensure representativeness across socioeconomic strata. Data collection instruments include structured questionnaires for household surveys, technical performance logs for the rainwater harvesting system, and semi-structured interviews with key stakeholders. The technical evaluation involves monitoring the system’s water collection efficiency, solar energy generation, and storage performance over a 12-month period, using data loggers and sensor measurements. The validity and reliability of instruments are established through pilot testing, calibration, and triangulation of data sources. Quantitative data will be analyzed through descriptive statistics, regression analysis to identify determinants of system efficiency, and comparative analysis across different climatic seasons. Qualitative data from interviews will undergo thematic analysis, guided by the Theory of Planned Behavior to understand community acceptance and behavioral influences affecting system adoption. The anticipated findings include a detailed model demonstrating the technical viability of integrating solar energy with rainwater harvesting infrastructure, insights into the factors influencing system performance under real-world conditions, and an understanding of socio-economic and policy barriers to widespread adoption. It is expected that the study will reveal that solar-powered systems can significantly enhance water collection efficiency—potentially increasing collection rates by up to 30%—and reduce reliance on traditional energy sources, thereby contributing to urban resilience and sustainability goals. This research contributes novel knowledge by providing a scalable framework for designing off-grid, renewable energy integrated rainwater harvesting systems in urban contexts and by empirically evaluating their performance in a developing country setting. It extends existing literature on sustainable water solutions by synthesizing technical, social, and economic perspectives, and offers policymakers, urban planners, and engineers evidence-based strategies for implementing green infrastructure. The main conclusion emphasizes that solar-powered rainwater harvesting systems are technically feasible and socio-economically acceptable solutions for urban water management. Recommendations include establishing supportive policy environments, incentivizing adoption through subsidies or tax reductions, and further research into optimized system configurations for different climatic zones. Future studies are suggested to explore long-term system durability, cost-benefit analyses, and integration with urban greywater recycling systems to create holistic sustainable water cycles in cities.