• University of Nairobi don says we could be in the longer-term climate cycles.
• National environmental ombudsman says conservation efforts must be ramped up or Kenya risks a serious disaster.
Image: MATHEWS NDANYI
Scientists are calling for thorough research to establish the cause of rising water levels in lakes in the country.
Tens of thousands have been displaced by rising water levels in lakes Victoria, Turkana, Baringo, Bogoria, Nakuru and Naivasha.
While the flooding has been attributed to heavy rains pounding various regions, experts say there is need for a study of the phenomenon.
Disruption of forests and water catchment areas and climate change are among other causes being attributed to the flooding in areas around the lakes.
Those living around Lake Turkana say they have not witnessed such a phenomenon in their lifetime. Baringo Governor Stanley Kiptis on Monday appealed for humanitarian aid for victims saying it was the first time water levels in Lake Baringo had risen to such a magnitude that left some 40,000 people displaced.
Professor Daniel Olago, the director of the Institute for Climate Change and Adaptation and a lecturer in the Department of Geology at the University of Nairobi, says there is no factual reason why these lakes are rising.
“No research has been undertaken to determine what the cause could be. Of course, we know that seasons change in rainfall but no analysis has been done to look at the right pattern and also at how the lakes levels have been rising and link the two,” Olago told the Star on Wednesday.
He said there are many possibilities for the occurrence including the likelihood that we could be in one of the longer-term climate cycles.
“Climate varies over different cycles such as El-Nino/La Nino phenomenon (which according to the US National Ocean Service can last nine to 12 months) and cycles that occur in 100 years and others that occur over 1,000 of years,” Olago said.
In the early 1960s, Kenya experienced heavy rains and the same happened in 1997/98 which was related to El-Nino.
Olago said the country has also experienced other heavy rain periods, saying that could be what is currently being experienced. He also attributed the problem to increased land degradation which has an effect on modifying the land surface so that you end up with higher rainfall-runoff.
“This then leads to higher amounts of water getting into the lakes. Under a land system that is not degraded, a lot of the water will filter into the soil due to the groundwater system, and less water will flow on the surface to enter the lakes," Olago said.
"Also related to this is the issue of soil erosion and enhanced sediment transfer from land into the lake, hence shallowing of the lakes. So while the amount of water may not have increased, water in the lake is rising because of the amount of sediment laid at the bottom of the lake.”
He said evaporation is also another factor to consider, explaining that effective rainfall depends on the ratio between precipitation and the amount of evaporation from the lake surface.
“So in a warm world, we expect to see more evaporation happening and if the precipitation- evaporation ratio changes (so evaporation is more dominant than precipitation) then you expect lowering of lake level. But if evaporation is suppressed, for whatever reason, then you expect more or higher lake level,” he said.
The don said what is happening now is, however, a very complicated mix of things that require various lines of research to be instituted "so that we are able to attribute what per cent of changes we are seeing is related to climate cycles, evaporation- precipitation ratio, amount of land degradation that has happened, how much is due to sediment erosion and deposition into the lake and how much is due to what is coming from under the earth or groundwater discharge into the lakes".
Dr John Chumo, the secretary of the National Environmental Ombudsman, said flooding of the lakes can be attributed to the disruption of the forests, adding that most of the catchments such as that of lakes Turkana and Baringo have been opened up.
“Initially, whenever there were rains, the forests would facilitate the evacuation of water into the underground to form underground water and fill the aquifers. Because of this, a lot of water would be in the soil or underground, but due to increased encroachment of the catchments, within a short time after it rains, water flows in the rivers all the way to the lakes. We've seen that in Lake Victoria, Lake Baringo and Lake Natron in Tanzania,” Chumo said on Wednesday.
"If we are not careful as a region, in terms of improving our forest cover, we may be staring at a serious disaster. We require serious afforestation to increase forest cover in all the water catchments including Mt Elgon and Mt Kenya.
Chumo said interventions in conservation of wetlands including those in Kericho, Narok, Kisumu, Nandi and Siaya counties should be urgently undertaken. Most of these wetlands have been degraded with people settling and farming on them. "The sooner we conserve the wetlands, the better,” he said.
Edited by P.O