Western Ghats Region At Risk From Rapid Soil Erosion: IIT-Bombay Study

A recent and unique study conducted by Prof Pennan Chinnasamy and Ms Vaishnavi Honap, at the Indian Institute of Technology Bombay (IITB), has revealed rapidly increasing soil erosion in the Western Ghats Region (WGR). The study incorporated remote sensing data to calculate the long-term soil losses across the entire landscape and it confirmed that a “progressive increase in soil erosion rates but also reveals alarming state-wise increase in soil erosion.”

In order to obtain the quantitative measures of the soil loss, the researchers have used the Universal Soil Loss Equation (USLE) method. USLE, being a convenient framework. considers factors such as rainfall, topography, soil erodibility, land cover management, and existing conservation practices to assess the data, and are “represented as process-based equations” to foresee the extent of soil loss concerning sediment yield and concentration. The employment of USLE for the WGR is new and possibly the first time such an assessment is carried out at this level.

By using data from 1990 to 2020, the researchers have quantified that the soil loss was 32.3, 46.2, 50.2, and 62.7 tons per year for the years 1990, 2000, 2010, and 2020 respectively. The study result underlines the alarming net increase of 94% in soil erosion, a shift which is harmful for the region’s biodiversity. Besides, the study also reflect that among the WGR states the state of Tamil Nadu marks the highest soil loss rate in WGR, “a staggeringly high increase of 121% from 1990 to 2020,” while Kerala, Karnataka, Goa, Gujarat, and Maharashtra, reflects an increase of 90%, 56%, 80% and 97% surge in soil losses respectively.

The increasing rates of soil erosion adversely affect ecosystem, biological diversity, and the communities that depend on the WGR, the study points out. Besides, it can result in lower agricultural productivity, reduce water quality, and impact freshwater sources, causing pertinent ecological and socioeconomic challenges.

The study finds that rising climate change combined with land mismanagement, act as the key factors to escalating soil erosion. As the next step, Mr Chinnasamy denotes: “future works include developing
scientifically validated and data driven best management plans (BMPs) based on the regional hotspots for soil loss.”