Enablers and Consequences of Landslide Outbreaks in Bududa District, Eastern Uganda

Abstract

Landslides are rapid movements of rock and soil on the Earth's surface, currently ranked among the most catastrophic environmental disasters worldwide. Bududa district, located on the steep slopes of Mount Elgon in eastern Uganda, has experienced a rising incidence of severe landslides. However, the environmental and human-driven factors contributing to these disasters remain poorly understood, hindering effective intervention strategies. This study investigated the causes, intervention strategies, and impacts of the persistent landslides in Bududa, aiming to generate insights for optimal solutions. A descriptive cross-sectional study was conducted, utilizing pre-validated semi-structured questionnaires and Key Informant Interviews to collect data from a random sample of 212 respondents, including household heads and district leaders. Additionally, 38 soil samples from landslide-affected sites in Bududa were analysed through experiments at Makerere University. This was complemented by observational surveys and digital photography. Qualitative data were analysed using thematic synthesis and photographic interpretation, while quantitative data were processed with descriptive and inferential statistics in STATA version 15.0. Graphs were generated using GraphPad Prism® version 9.0.0. In the findings, factorial analysis of variance (FANOVA, p<0.05), showed that the high soil- organic content (p<0.001), bulky density (p=0.002) and water saturation levels (p=0.011), in addition to other environmental factors such as the steep terrain and heavy rains are the cardinal mediators of landslide outbreaks in Bududa, while soil porosity (p=0.718) and permeability (p=0.267) were not implicated. These environmental drivers were found to be noticeably moderated by the widespread incidence of unregulated anthropogenic activities, primarily human settlement, infrastructural development and monetary enterprises like agriculture and cutting of trees. While some positive outcomes of landslides were acknowledged such as survivors improving their livelihoods after relocation, there was strong consensus on the adverse impacts, including casualties and deaths, and significant damage to infrastructure, agriculture, the economy, and social services. The majority of respondents confirmed the widespread presence of awareness campaigns, multisectoral collaborations, and mechanical preventive measures like physical mapping. Most participants agreed that tree planting could reduce landslides and that external support would enhance coping strategies in Bududa more effectively than local resources. However, they were uncertain about the effectiveness of existing local defensive measures, such as slope geometry modification. Additionally, monitoring for future outbreaks, household micro-land use interventions, and promoting slope stability were perceived as inadequate. Conclusively, reliable evidence was generated, indicating that the main factors enabling the recurrent landslides in Bududa are tri-faceted. That is, natural topography and soil characteristics, climate, and human influence. Consequently, strengthening the cooperative participation of stakeholders from sectors related to those three facets may improve the results of interventions.