Quantitative soil erosion risk assessment due to rapid urbanization in the Cox’s Bazar district and Rohingya refugee camps in Bangladesh

Abstract

Soil erosion due to anthropogenic interventions is an emerging threat to the south-eastern coastal districts of Bangladesh. In the recent decade, land degradation intensified this process in this region due to the settlement of the Forcibly Displaced Myanmar Nationals popularly known as ‘Rohingya’, who fled from Myanmar in 2017. To control soil erosion, it is necessary to identify the soil erosion locations and their intensity. The present study has attempted to quantify the regional soil loss (from 2015 to 2020) using the Revised Universal Soil Loss Equation model. In this method, soil erosion risk assessments are carried out by integration of different physiographic parameters in the spatial dimension. Results showed that the year 2015 and 2020 witnessed mean soil erosion at a rate of around 58.2 and 59 t ha− 1 yr− 1, respectively in the Cox’s Bazar district in which 20–21% of the study area was highly subjected to soil erosion. But in the Rohingya camps mean soil erosion for these periods is 59 and 78 t ha− 1 yr− 1, respectively with a cumulative increase of 32%. The sub-districts adjacent to the Rohingya refugee camps (Ramu, Ukhia, and Teknaf) have experienced intense erosion compared to the others. From 2015 to 2020, a large increase of about 4.54 (6%) t ha− 1 yr− 1 is observed in the Palongkhali union whereas a maximum decrease of about − 8.08 (23%) t ha− 1 yr− 1 is observed in the Pokkhali union. In Rohingya camps, the worst soil erosion-affected areas are the camps 8E, 10, 14, 15, 16, and 17 having more than 100 t ha− 1 yr− 1 mean soil loss. The geographic detector method is used to identify the influence of different factors on soil erosion. Land use change is found to be the major contributing factor to soil erosion increase from 2015 to 2020. The spatial variations are significantly controlled by slope and elevation factors. This work can help to understand the dynamics of soil erosion and the knowledge can be used for conservation planning in the Cox’s Bazar and Rohingya camp areas.