The government of Tanzania has issued a temporary ban on the use of water from the Mara River following suspicions of pollution. There were reports of a bad smell emanating from the Talek River, a tributary of the Mara River that runs through the Masai Mara game reserve in Kenya before the Mara flows into the Serengeti in Tanzania.
In Tanzania, reports of the river turning blackish and sightings of dead fish on its surface led to the launch of an investigation into the pollution of the possible poisoning of the river. The Minister of State in the Vice President’s Office, Selemani Jafo, formed a team of 11 experts to conduct water quality analysis.
As the cause of the problem was unknown, a broad range of experts were appointed to investigate. In the meantime, the use of the river’s water for domestic purposes was banned in four villages and the Rural Water Supply Agency was tasked with finding an alternative water supply for these villages.
The Mara River basin covers an area of 13,504 km², of which some 65% is located in Kenya and the remaining 35% is located in Tanzania. It is home to one of the most famous tourist destinations in the world, i.e. the Masai Mara and Serengeti parks, which features the annual migration of wildebeest.
The basin has undergone changes in land cover as well as land use: in the upper basin large parts of the natural vegetation of the savannah and Mau Forest have been cleared for agricultural development and human settlement. As a result, there has been increased siltation of the river, and the base flow in the dry season is lower than normal due to the reduced sponge function of the forest.
In the past, researchers have noted such fish kills and attributed them to hypoxic floods, or floods of water with low oxygen content. These may be caused by the flushing of hippopotamus pools, releasing their defecation into the river channel and resulting in sharp drops in oxygen content of the river.