Sanitation infrastructure and faecal flow – SanIFFlow: a spatial mapping tool for integrated planning and management of sanitation in unsewered urban areas

Proper sanitation is vital for public health, particularly in urban areas. However, planning and managing sanitation systems in secondary cities within economically developing countries presents persistent challenges, largely due to a lack of spatial understanding and representation. To address these challenges, this study introduces SanIFFlow (Sanitation Infrastructure and Faecal Flow), a spatial analytical approach focused on a city-scale, ward-level model. SanIFFlow provides an actionable insights into infrastructural attributes and faecal flow dynamics, tailored to the practical governance capacities of the city's existing management framework. By leveraging open-source data on buildings, population, and drainage network, the method offers a detailed spatial representation of faecal matter sources and movement pathways within urban catchments. This approach enables strategic sanitation planning and proactive management, identifying high-risk areas and supporting targeted interventions, such as ward-level infrastructure upgrades. SanIFFlow represents a scalable, data-driven tool designed to enhance urban sanitation management in resource-constrained settings.