Influence of Rainfall Characteristics on Landslide Occurrence In Bududa District, Mount Elgon Region

Abstract

The communities of Bududa district recurrently experience landslide events during rainy season. The frequency and intensity of these landslides are increasing over the years because of heavy rainfall occurring over a few days. Daily rainfall data for the periods 1986 to 2018 from CHIRPS portal was obtained and landslide records for the period were obtained from Global Landslide catalog available on https://catalog.data.gov/dataset/global-landslide-catalog-export. With these, the rainfall characteristics were examined in relation to landslides occurrences. To determine the trends in rainfall characteristic, Mann-Kendal trend analysis method was used as well the Coefficient of Variation. Linear regression model was used to generate the rainfall threshold causing Landslide in Bududa district. Results reveal positive linear trends for the period 1986 to 1996 and 2008 to 2018 while negative linear trend was observed in the period of 1997 to 2007. The threshold computation suggested that about 105mm of accumulated rainfall can trigger landslide events in Bududa district. However, there is need for continuous monitoring of the landslides in the area by concerned research institutions and local authorities for validation of the proposed threshold and caution must be taken as the thresholds were defined statistically, using a limited, geographically biased, and certainly incomplete dataset when adopting this work to establish operational landslide warning systems.