The United Nations Office for the Coordination of Humanitarian Affairs (UNOCHA), have stated (October 2010) that one of their key concerns in Eastern Uganda is flooding and landslides as a result of environmental degradation.
Eastern Uganda is generally a flat plateau, with the border between Kenya and Uganda dominated by the beautiful hills and slopes associated with Mount Elgon, an extinct shield volcano. These slopes are home to a number of communities. The higher elevation provides a more moderate climate than the plateau below, and the fertile soils are used by communities to grow crops, especially coffee. The slopes are also home to a wide variety of plants and forest – although a deforestation programme has been taking place in recent years.
|Foothills of Mount Elgon|
The slopes of Mount Elgon have been prone to a number of landslide events, as can be seen on aerial photographs. One of the biggest was this time last year (March 1st 2010) in Bududa. This landslide was preceded by significant rains. The slopes of Mount Elgon are the catchment area for a number of streams and rivers. The heavy rain caused a significant swell of these, and groundwater levels to rise. As groundwater levels rose, the instability of the slope increased due to the decrease in effective stress. This was likely exacerbated by the deforestation, with the soil losing anchorage and surface erosion more likely.
The total impact and effects of this landslide are unknown. Estimates of those who died are currently about 388, and significant numbers were left displaced as soil, mud and boulders submerged three villages. A number of school pupils took shelter in a health centre, which was tragically then destroyed.
As Uganda is entering a new rainy season one year on – there is a possibility that old landslides will be reactivated and new landslides occur. So what can be done to help reduce the tragic loss of life and economic costs of these disasters? In many ways it is hard to answer this question without fully understanding the landslide mechanisms and causes.
The Government of Uganda has criticised the communities for living in these high-vulnerability places, and advised that people move off the landslide prone slopes. This is, however, around half a million people – most of whom are subsistence or crop farmers. Relocating this amount of people, and finding the land for them to make a living, is no easy task. A review of vulnerability in the area could give more specific advice on which communities to relocate – but if crop yields (coffee etc) are less productive than their original plots, it may be difficult to persuade people not to return.
Research published this year in the African Journal of Agricultural Research suggests that farmers have a reasonably good knowledge of where landslides might hit, and some things they avoid (such as terracing) that can trigger landslides. The research suggests that possible interventions could be done using participatory methods. This would aim to help farmers better recognise causes and effects of landslides, and reduce activities that lead to instability - such as undercutting slopes for house construction. The research did not, however, discuss the effects of deforestation with the farmers. It is also unlikely that the threat could be removed simply by getting the farmers to change some practices. A bigger scale intervention, reseeding degraded land, planning and organising the slope-sided farming and improving drainage on the slopes would also be required.
|Foothills of Mount Elgon: Concave Slopes identified by farmers as areas more vulnerable to landslides|
It is likely that the best way to help reduce the effects of landslides in this area is a combination of a number of things:
- Relocation in some areas of very high risk
- Working with farmers to ensure their farming is more sustainable and avoids environmental degradation. Offering alternative housing styles to prevent the need for undercutting slopes.
- Some possible engineering solutions - improving drainage and increasing toe weights to prevent instability.
It is hoped that the Ugandan Government and their development partners will act strongly to reduce the possibility of future disaster in this area.