Natural cycle, increase in rainfall amounts and catchments degradation causing lake overflow

A natural fluctuation cycle, heightened rainfall in Eastern Africa, and catchment degradation are the main factors contributing to the rising water levels in the rift valley lakes, according to recent studies. Since 2010, the lakes have been experiencing increased water levels, with the peak occurring between 2014 and 2016, coinciding with a strong El Nino event.

Researchers from the region, namely paleoclimatologists and paleoecologists, have been investigating this phenomenon by analyzing sediments from the lake bottoms, examining organic geochemistry, and dating the sediments using carbon-14 dating. They have discovered that the lakes have experienced several fluctuations, both on inter-annual and decadal scales, and that these lakes have previously dried out and reached higher levels than the current ones.

Additionally, Prof. Daniel Olago, an environmental geoscience professor at the University of Nairobi, suggests that deforestation, increased surface runoff, and erosion are exacerbating the situation, as the eroded sediments flow into the lakes, increasing the amount of sediments at the bottom. He highlights that small changes in rainfall can have large hydrological responses, as demonstrated by historical examples where rainfall changes of 10-30% led to significant alterations in lake levels.

The professor warns that the lakes' chemistry is set to change, particularly for Lake Baringo and Lake Bogoria, due to their degradation caused by deforestation, poor farming practices, and unsustainable pastoralism. He emphasizes that nature-based solutions, such as regenerating the catchments, can help mitigate the situation, as more rainfall water would seep into the ground, reducing surface runoff.