Community-based Urban Rainwater Harvesting: Design, Implementation, Evaluation

Thesis Abstract

Urban areas face increasing pressure on both water security and stormwater management due to urbanization, climate variability, and aging infrastructure. This study investigates community-based urban rainwater harvesting (URWH) as a design, implementation, and evaluation solution to enhance resilience, reduce runoff, and augment potable and non-potable water supplies in a mid-sized metropolitan context. The aim is to design scalable URWH systems integrated with existing housing and community facilities, implement a pilot across diverse neighborhoods, and evaluate technical performance, socio-economic viability, and policy-enabling factors. Specific objectives are (i) to develop a participatory design framework for URWH that aligns with local hydrology, building typologies, and spatial constraints; (ii) to implement 60 household-scale and 12 community-scale URWH units over a 12-month pilot, incorporating first-flush devices, modular storage, gravity-fed distribution, and user-interface dashboards; (iii) to assess water savings, runoff reduction, and system reliability using pre- and post-installation water meters and rainfall data; (iv) to evaluate user acceptance, operation and maintenance costs, and equitable access through mixed-methods inquiry; and (v) to identify governance, financial mechanisms, and policy levers that facilitate scale-up. The methodology adopts a convergent mixed-methods design within a realist evaluation framework. The population includes urban households, community centers, and building managers within the city’s periphery. A stratified random sample of 240 households is selected for quantitative measurement, while 40 stakeholders participate in in-depth interviews and 8 focus groups to capture behavioral and institutional insights. Data collection instruments comprise calibrated water meters, rainfall collectors, a standardized URWH operational checklist, and semi-structured interview guides. Instrument validity is established via content validity panels comprising hydrologists, urban planners, and social scientists; reliability is tested through a pilot with 20 households. Quantitative data are analyzed using descriptive statistics, paired t-tests, and multiple regression to determine relationships between rainfall, system performance, and water savings; ANOVA tests examine differences across neighborhood types. A difference-in-differences approach assesses pre/post hydrological impacts. Qualitative data are subjected to thematic analysis guided by Braun and Clarke’s method to elucidate user behavior, perceived benefits, and barriers. A conceptual model integrating socio-technical factors—utilization, maintenance, finance, governance, and policy context—is developed and tested against empirical findings. Key expected findings include (i) a quantifiable reduction in municipal water demand of 18–28% among participating households, and a 22–35% decrease in surface runoff during peak rainfall events; (ii) high reliability with 92% system uptime driven by standardized first-flush and filtration components; (iii) strong positive correlation between user engagement and sustained water savings, moderated by maintenance affordability; (iv) evidence of improved neighborhood cohesion and willingness to participate in future shared infrastructure, contingent on accessible financing and transparent governance; and (v) policy constraints identified, including permit requirements, retrofit incentives, and cross-subsidies needed to scale URWH. The study contributes to knowledge by integrating design, community engagement, and empirical evaluation of URWH within an urban governance framework, advancing a transferable model for scalable, low-cost rainwater harvesting that aligns with climate adaptation and water security objectives. Theoretically, it extends Applied Urban Hydrology and Social Practice theories by linking technical performance with everyday routines and collective action in municipal contexts, and it draws on the Theory of Planned Behavior to interpret maintenance behaviors. The conclusion emphasizes that URWH can be an effective, equitable urban resilience strategy when designed participatorily, supported by targeted financial incentives and enabling policies. Recommendations include adopting modular URWH kits for rapid deployment in varied housing stock, establishing municipal microgrants for maintenance subsidies, creating community water stewards programs, and integrating URWH targets into urban development plans and climate action strategies.