Controlling soil erosion and landslides through ecosystem-based adaptation interventions in the hilly landscape of western Rwanda

Ecosystem-based Adaptation interventions such as protective vegetation, soil and water conservation measures and re-vegetation of degraded land have shown promise in reducing soil erosion and landslides occurrence. The western province of Rwanda has experienced destructive natural hazards especially soil erosions, floods and landslides. This study aimed to assess the contribution of Ecosystem-based Adaptation interventions on the reduction of soil erosion and landslides in the hilly landscape of Western Rwanda with a case study of Rubyiro sub-catchment in Rusizi District. Methods used in data collection comprised remote sensing techniques combined with a questionnaire survey to collect perceptions of farmers conducting agricultural activities in the catchment where Rusizi District has implemented Ecosystem-based Adaptation (EbA) interventions. The Revised Universal Soil Loss Equation (RUSLE) model combined with Geographic Information System (GIS) and remote sensing tools were used to assess soil loss pre- and post-EbA interventions. The results of the survey indicated that after four years of EbA interventions, the number of landslide occurrences was reduced at a rate of 62.6 %. The respondents who appreciated forest restoration to minimize landslides were 72.4 %, progressive terraces 26.1 % and bench terraces 1.5 %. The estimated average annual soil losses were 11.9 tons/ha/year, 17.6 tons/ha/year, 10.1 tons/ha/year, 9.3 tons/ha/year in 2017, 2018, 2021 and 2022, respectively. This indicates a reduction of 8.3 tons/ha/year from 2018 to 2022 as opposed to an increase of 5.7 tons/ha/year recorded from 2017 to 2018. Thus, EbA interventions made a great contribution to the reduction of soil erosion and landslides in the Rubyiro sub-catchment, and they can be recommended in other similar hilly landscapes.