Scientists urge urgent action to save Monik River in Ngorongoro

ARUSHA : Scientists are warning that failure to act early to protect Monik River in Ngorongoro District could lead to costly environmental restoration in the future, as new research shows early signs of ecological stress linked to farming, livestock keeping and other land use activities along its catchment. The warning comes from a study conducted by researchers led by Mussa Paul, Tumpale Mwakasangula, and Hassan Mrutu from the Water Institute (WI), and Isabela Mkude of the Open University of Tanzania (OUT), which assessed seasonal and spatial changes in water quality along the river. Although Monik River still meets water quality standards set by the World Health Organization (WHO) and the Tanzania Bureau of Standards (TBS), the researchers caution that this does not mean the river is free from risk. WHO water quality guidelines are international health benchmarks used to assess whether water is safe for human use, particularly drinking and domestic purposes. They set limits for nutrients, organic pollution, and microbial contamination to prevent health risks. TBS standards, on the other hand, are Tanzania’s national regulatory thresholds used to determine acceptable water quality for environmental safety and public use within the country. In both frameworks, water that falls within limits is considered safe or acceptable, but scientists stress that trends over time are equally important, especially when indicators begin to rise even if they remain within permitted thresholds. In the case of Monik River, researchers say rising levels of sediment, nutrients, and organic matter during rainy seasons point to increasing pressure on the ecosystem. “The results indicate that livestock keeping, deforestation, agriculture, and other human activities contribute to the transport of nutrients, sediments, and organic matter into the river through surface runoff,” the researchers state. The study found that water quality deteriorates most during the rainy season, when runoff carries soil particles, fertilizers, and organic waste into the river, increasing turbidity and organic pollution levels. It also identifies a clear spatial pattern, with water quality indicators rising from upstream to midstream sections where human activities are concentrated, before improving downstream where pressure is lower. According to the researchers, these patterns show a gradual shift in ecological balance rather than random variation, warning that continued pressure could accelerate degradation if no action is taken. “The river is still within acceptable limits, but the observed variations indicate increasing pressure from human activities that require immediate management interventions,” the study notes. Despite these early warning signs, the researchers emphasize that Monik River is not yet heavily polluted but is experiencing moderate environmental stress that can still be reversed through preventive action. Environmental experts say delaying intervention could significantly increase future costs. Juma Daudi, a water resources specialist based in Arusha, noted that once river systems degrade beyond a certain point, restoration requires large-scale engineering works, long-term rehabilitation programmes, and sustained financial investment. “When degradation becomes visible, governments are forced into expensive interventions such as riverbank reconstruction, sediment removal, and water treatment upgrades. Preventing that stage is far cheaper than correcting it later,” he said. To avoid such outcomes, the study recommends immediate restoration of vegetation along riverbanks to create riparian buffer zones that filter pollutants and stabilize soil. It also calls for stricter control of livestock access to riverbanks through designated watering points and alternative water sources, arguing that uncontrolled grazing increases erosion and contamination risks. Improved agricultural practices, including controlled fertilizer use and soil conservation methods, are also recommended to reduce runoff during rainfall. The researchers further urge increased public awareness of the impacts of deforestation, sand harvesting, and riverbank cultivation, alongside regular monitoring of water quality trends. They also recommend the development of alternative water sources such as boreholes and wells to reduce direct dependence on the river. Conservation advocates warn that continued pressure on feeder rivers like Monik could eventually affect downstream ecosystems linked to Lake Natron, a wetland of international ecological importance. Jane Huruma, a conservation activist, said enforcement of environmental regulations remains weak despite growing scientific evidence. “The knowledge is already there. What is missing is consistent enforcement and real commitment at community level. Without that, these recommendations will remain on paper,” she said. She adde