Case study: Baringo County, Kenya

A nation of lakes

Out of the 667 lakes in Africa, 64 of them are in Kenya. Part of this extensive lake system runs through The Great Rift Valley, which runs from Lebanon down to Mozambique and cuts a backbone through central Kenya. It protrudes at the joining of divergent tectonic plates, producing the lakes and volcanoes along it's ridge-line. The main inflow to the Valley within Kenya is from Lake Turkana in the north, which itself receives inflows from the Omo River in Ethiopia.

Figure 1: Map showing all the locations in mentioned in this blog. 

Source: Google Earth

Despite it's considerable lakes, Kenya's overall land area is 80% classified as arid and semi-arid land. When thinking about environmental change in relation to Africa, the negative connotations of dry lakes and wells spring to mind. In 2010, the Rift Valley lakes were at their lowest levels since 2002. As a consequence, studies found that it was expected that a warming climate would result in the lakes throughout the valley drying up but the intensification of the hydrological cycle over the last decade has actually caused the lake levels to rise.

A town concerned

Prompted by local populations in the small town of Marigat, a Kenyan geologist named Simon Onywere checked recent satellite imagery of Lake Baringo. The people in the town claimed the local school was close to flooding. He noticed that the shoreline of the lake was changing year by year. By the time him and his peers at various universities had furthered their investigations, towns and populations living on the banks of the Baringo had flooded and resulted in the displacement of the people living there.

Figure 2: Map of the Lake Baringo area. Source: Google Earth

Marigat is main income is lake-fed irrigation agriculture and the soil quality across Baringo has been considered low. Rising lake levels have caused further water erosion of the soils, reducing nutrient levels and causing siltation of the soil. Away from Marigat, Baringo County's economy is reliant on raising livestock. Flooding not only reduces space for this livestock but reduces food sources for the grazing animals.

Figure 3: A livestock grazing area in Baringo County, September 2013. 

Source: Obando et al., 2016

But why the rise?

It is not unusual for flooding to occur in Kenya but the Rift Valley lakes are particularly sensitive to changes in the hydrological cycle. Baringo County's main lakes, Baringo, Bogoria, Naivasha and Nakuru, are generally small, shallow and in endoheic basins. Even small changes to inflows and evaporation levels will cause large fluctuations in water level. From 2010 to 2013, precipitation levels were consistently higher than average and with no outflows, these lakes engorge. Geoscientists have also theorised that the tectonic activity could have introduced geothermal water to the system. Not just affecting the agricultural industry, flooded areas have seen an increase the spread of disease, bites from displaced snakes and increased crocodile attacks. 

Conclusion

There is need for more research on the short and long term impacts of this increase in water level needs further study. The infrastructure of the area needs updating as well, as the rising lake levels resulted in the gauging stations becoming totally submerged.