NEW DELHI, July 20: Laitkynsew and Sohra region of East Khasi Hills in Meghalaya are the most vulnerable regions to rainfall erosivity, while the Shahi Kangri Mountain region of Ladakh is the least vulnerable, according to the Indian Institute of Technology Delhi’s pan-India assessment of rainfall induced erosion across India.
Erosivity is the term used to describe the potential of raindrop impact, runoff from snowmelt, or water applied with an irrigation system rainstorm to detach and erode soil.
Researchers at IIT Delhi have developed a map to highlight areas prone to rainfall-induced erosion in India which they claim will help in planning, prioritising, and implementation of essential watershed development activities to minimise soil erosion.
According to the team, soil erosion induced by rainfall has been identified as a significant environmental problem globally. The current assessments of rainfall erosivity in India are limited to catchment or regions specific, which is very less to assess rainfall erosivity for a nation like India, having diverse climate properties.
“About 68.4 pc of the total eroded soil in India is affected by erosion induced by water, and rainfall erosivity (the potential of rain to cause soil degradation), is a major contributor to it. Soil erosion induced by rainfall has been identified as a significant environmental problem globally,” said Manabendra Saharia, Professor, Department of Civil Engineering, IIT Delhi.
“The current assessments of rainfall erosivity in India are limited to catchment or regions specific, which is very less to assess rainfall erosivity for a nation like India, having diverse climate properties,” he added.
Using multiple national and global gridded precipitation datasets — Indian Monsoon Data Assimilation and Analysis (IMDAA) at an hourly temporal scale, India Meteorological Department (IMD) on a daily scale, and the Global Climate Hazards Group Infrared Precipitation with Station data (CHIRPS) on a daily scale, the researchers have developed a high-resolution map highlighting areas prone to rainfall-induced erosion in India.
“This study is a step toward building a national-scale soil erosion model for India. The national rainfall erosivity map will facilitate watershed managers to identify rainfall erosivity potential at diverse locations and thereby plan, prioritize, and implement essential watershed development activities to minimise soil erosion,” said Saharia.
According to the study, which was published in CATENA, the average rainfall erosivity (R-factor) value estimated for India is 1200.
Catena publishes papers describing original field and laboratory investigations and reviews on landscape evolution and geoecology with emphasis on interdisciplinary aspects of soil science, hydrology and geomorphology.
“The most vulnerable region to rainfall erosivity (R-factor of 23,909.21) was spotted in the Laitkynsew and Sohra region of East Khasi Hills (one of the wettest regions in the world), while the least vulnerable region (R-factor of 8.10) was spotted in the cold and dry Shahi Kangri Mountain region of Ladakh,” said IIT Delhi PhD student Ravi Raj. (PTI)
