Researchers develop map to highlight areas prone to rainfall-induced erosion in India

New Delhi: At the time when monsoon has brought flood-like situations to various parts of the country, a team of researchers at the Indian Institute of Technology, Delhi, have come up with the first pan-India assessment of rainfall erosive over India. The study comes at a time when soil erosion induced by rainfall has been identified as a significant environmental problem globally.

The said study has been conducted at Hydrosense Lab, IIT Delhi by PhD student Ravi Raj, Professor Manabendra Saharia, and Professor Sumedha Chakma from the Department of Civil Engineering. Using multiple national and global gridded precipitation datasets i.e., 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 (Figure 1) highlighting areas prone to rainfall-induced erosion in India.

According to the study, which was published in CATENA, a distinguished science journal, the average rainfall erosivity (R-factor) value estimated for India is 1200 MJ-mm/ha/h/yr. The most vulnerable region to rainfall erosivity (R-factor = 23,909.21 MJ-mm/ha/h/yr) was spotted in the Laitknsew and Cherrapunji region of East Khasi Hillis in Meghalaya state (one of the wettest regions in the world), while the least vulnerable region (R-factor = 8.10 MJ-mm/ha/h/yr) was spotted in the cold and dry Shahi Kangri Mountain region of Ladakh.

The study also proposed several empirical equations that can be used by field practitioners. Parts of Assam and Meghalaya are among Indian zones prone to the most significant rainfall-induced soil erosion having R-factors of the highest range. Having soil of mostly loamy, silt loamy, sand clay loamy, and clay loamy, texture classes and slopy terrain do not show great resistance to soil erosion due to water. The concerned authorities need to adhere to adequate soil conservation measures.