RESEARCH ARTICLE Impact of 2018 Kerala Floods on Soil Erosion: Need for Post-Disaster Soil Management Pennan Chinnasamy 1,2 • Vaishnavi Uday Honap 3 • Ambadas Bandu Maske 3 Received: 1 November 2019 / Accepted: 27 August 2020 Ó Indian Society of Remote Sensing 2020 Abstract Extreme precipitation events lead to flash floods, which can trigger soil erosion and landslides. While damages to infrastructure and livelihoods are rapidly assessed on economic terms, damages to natural resources are not estimated due to limited observation record. This study conducted an analysis using remote sensing data to estimate changes in soil erosion rates before, during and after the Kerala 2018 floods, based on the Universal Soil Loss Equation (USLE). The USLE was driven by multiple data including: in situ rainfall data from Indian Meteorological Department (to estimate rainfall erosive factor), soil maps prepared by Food and Agriculture Organization (to estimate the soil erodibility factor from the properties of soil that consists of the percentage of clay, loam and silt), digital elevation model (to estimate topographic slope and length) from Shuttle Radar Topography Mission and multispectral imagery (to estimate cover management factor and conservation practice factor) from Landsat-8 satellite. Data from these sources were analysed using a Geographic Information System (GIS) platform. Results indicate a state-wise average increase of 80% (31–56 metric tons ha -1 year -1 ) in soil erosion rate during the floods. Of the districts, Idukki showed the highest increase, of 220% and more susceptibility to soil erosion, which is in comparison with government survey records. Results show that the floods and associated erosion were not only due to the rainfall event but also due to the rapid change in land use and land cover, from natural to human settlements. Therefore, government agencies need to protect land cover and reduce unsustainable development in ecologically sensitive environments, which if managed properly can act as a buffer for soil erosion extremes in Kerala. Keywords Floods  Soil erosion  Kerala floods  Landslides  Sedimentation Introduction Climate change-induced disasters are increasing globally and affecting almost every country, especially developing and under developed nations (Chinnasamy and Sood 2020; Lacombe et al. 2019). Of such calamities, extreme pre- cipitation and associated flooding have become one of the most devastating phenomena induced by climate change (Chinnasamy 2017). Frequency of such floods and extreme events has been steadily increasing in the past decade, and in some cases, ordering for a change in the flooding indices such as flood frequency (e.g. definition of 100-year flood) or recurrent flood levels (Milly et al. 2002; Guhathakurta et al. 2011). Even with rainfall and flood prediction models, the impacts of heavy rainfall and flood are challenging to contain and prepare. As such, mitiga- tions and adaptation plans are often post-disaster, i.e. ‘‘reactive’’ and less prepared before natural calamities, i.e. ‘‘proactive’’ measures. Across the world, annually, millions of people are directly impacted by heavy rainfall events and floods, especially due to heavy damage on infrastruc- ture and agricultural sectors. Such damage and impact have & Pennan Chinnasamy p.chinnasamy@iitb.ac.in Vaishnavi Uday Honap vaishnavihonap6399@gmail.com Ambadas Bandu Maske maskeambadas@gmail.com 1 Indian Institute of Technology, Bombay (IITB), Powai, Mumbai, Maharashtra 400076, India 2 Rural Data Research and Analysis (RuDRA), Powai, Mumbai, Maharashtra 400076, India 3 College of Engineering, Pune, Wellesley Road, Shivajinagar, Pune, Maharashtra 411005, India 123 Journal of the Indian Society of Remote Sensing https://doi.org/10.1007/s12524-020-01162-z