Author(s): Rocky Talchabhadel, Anil Aryal, Manisha Maharjan, Rajaram Prajapati, Hajime Nakagawa, Kenji Kawaike

Linked Author(s): Hajime Nakagawa, Kenji Kawaike

Keywords: Climate change; Nepal; Rainfall erosivity; Representative concentration pathway; Soil erosion;

Abstract: In this paper, we have assessed the anticipated impacts of climate change (CC) on rainfall erosivity over Nepal. Soil erosion is an ongoing geomorphic process for which rainfall is one of the active drivers. The significant effect of CC on the soil erosion process is the change in the erosive power of rainfall due to variations in rainfall patterns, amounts, and intensities. The study assesses rainfall erosivity of revised universal soil loss equation (RUSLE) historical time (1961-1990), mid future (50s: 2041-2060) and far future (70s: 2061-2080). Ensembles of ten selected General Circulation Models (GCMs) from WorldClim under two representative concentration pathways (RCP 4.5 and RCP 8.5) were used for projected analysis. Wischmeier and Smith, (1978)’s approach was used to estimate rainfall erosivity. This study provides an overview of changes in rainfall erosivity (past and projections) and discusses the potential impacts on soil erosion across the country. The rates of change in precipitation and resulting rainfall erosivity are relatively more under RCP 8.5 than RCP 4.5. During 70s, annual precipitation is projected to increase by 8.1 % under RCP 8.5. We found that the annual rainfall erosivities are expected to increase by 27.8% in high mountain, 17.76 % in upper hill, 17.7% in mid hill, 19.68% in siwalik, and 16.5% in tarai plain of the country in far future under RCP 8.5 with respect to historical time. Our study suggests the scenario of CC in the future will increase soil erosion based on just the effects of the rainfall erosivity factor.

DOI: https://doi.org/10.3850/38WC092019-1264

Year: 2019