Climate variability impacts on sanitation services in an informal urban settlement of Tandale Ward in Dar es Salaam Tanzania

Global efforts to expand access to sanitation are challenged by climate variability, which disrupts Faecal Sludge Management Services (FSMs) including pit/septic tank emptying operations, transportation, treatment processes at drying beds and treatment plants, routine operation and maintenance of facilities, and safe disposal from onsite sanitation systems. This study conducted in Tandale Ward, a low-lying area with informal settlements explores the impact of rainfall variability on faecal sludge management. Analysis of rainfall data revealed significant variability, with an annual CV of 28.08 %, 31.8 % in long rains, 47.0 % in the dry season, and 51.4 % in short rains. The short rain season showed irregular rainfall distribution, with PCI values exceeding 20 % in 1991, 2002, and 2008. SAI analysis highlighted anomalies, particularly a strong positive SAI in 2017 (2.9), an exceptionally wet year. The Mann-Kendall test revealed a moderately increasing trend in annual and seasonal rainfall, with a significant rise during the dry season. High PCI values are associated with flooding, potentially leading to overloaded containment systems, frequent latrine overflows, and contamination of water sources. Conversely, low SAI values are related to prolonged droughts that reduce water availability, disrupting faecal sludge emptying, transportation, and treatment operations. These findings underscore the importance of integrating climate data into sanitation planning to enhance the sustainability and resilience of FSM systems.