Assessment of Mara River water quality in Tanzania under data constraints using the Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI)

The Mara River is a vital transboundary watercourse shared by Tanzania and Kenya, sustaining diverse ecosystems and socio-economic activities. Notwithstanding its importance, the river faces increasing challenges from anthropogenic activities that threaten its water quality and long-term sustainability. This study assessed the water quality of the Mara River reach in Tanzania by using the Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI) under data-limited conditions. A total of 16 sampling locations were established along the river, representing key zones of potential pollution sources. Water samples were collected and analyzed in-situ and in accredited Laboratory during three years, 2022, 2024, and 2025, to evaluate the Physicochemical parameters. The results indicated that the average values of temperature is 26.7±2.9 0 C, pH 7.8±0.65, Electrical conductivity 433.6±380μS/cm, Total Dissolved Solids 239±223 mg/L, Turbidity 181.9±173NTU, and Dissolved Oxygen 4.77±3.01 mg/L. The overall CCME-WQI average was 87.03%, classifying the Mara River water quality as “Good”. However, localised degradation was observed near agricultural, mining, and urban discharge zones, emphasising the need for improved management practices and pollution control measures. This study contributes essential baseline information for sustainable river basin management and supports evidence-based policy interventions for the conservation of Mara River ecosystem