A few days before the Save the Elephant research site was washed away by a flash flood, villages along on the western flank of Mt Elgon were hit by landslides, killing at least 100.
Minister David Wakikona, MP for Manjiya County in Bududa district, said
“Everybody is dead. 320 people are unaccounted for. I don’t know if we shall get any survivors out.”
The trigger was also heavy rain associated with the onset of the March-May rainy season. And while landslides are always to be expected sooner or later on steep terrain, this area had became more susceptible since the 1960s due to land clearance for crops and fuel.
I visited the area in 2008. The local Uganda Red Cross team gave me a tour of the mountain side and I met the elders of one of the villages above Mbale. Both the Red Cross and the villagers were concerned about landslides and rock falls that had claimed several lives. And the village elder seemed at least vaguely clued up about the cause: deforestation. That said, Oxfam released a report in August 2008 about the potential impacts of climate change on Uganda, and suggested climate change would increase the danger of landslides. While that may be true, I think it is rather useless – the important factors around Mt Elgon at least is deforestation and village vulnerability.
Trees reduce the tendency for soil-mantled slopes to fail in three ways, though not all are relevant at any one site or time. The most obvious is that their deeper and stronger roots bind the soil together vertically and laterally; they may also bind the soil to underlying bedrock if shallow enough. The heavier trees increase the friction of any failure surface within the soil. And the higher transpiration of the trees can dry up the soils more, thus requiring more water-logging for slope failure to occur. Trees are also helpful in limiting the run-out distance of rock falls by serving as a natural debris belt.
With this in mind, the main recommendation I gave to the Red Cross and villagers was to plant fruit trees. They are so below the poverty line that they need both nutritional or economic assistance as well as protection from landslides. Fruit trees hits two birds with one stone. It reduces their vulnerability and increases their resilience to the next natural hazard.