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INTRODUCTION
Kerala, a state in south-western India, has faced significant flooding events in recent years, particularly from 2018 to 2022. These floods have caused extensive damage to infrastructure, agriculture, and livelihoods, and have resulted in considerable human and economic losses. The increase in the frequency and intensity of these floods has drawn attention to the critical need for detailed analysis of flooding patterns and causes. Understanding these patterns can assist in better flood management, preparedness, and mitigation efforts.
Spatiotemporal analysis using Geographic Information Systems (GIS) offers powerful tools to map, analyze, and interpret flooding dynamics over time and space. By integrating hydrological data with GIS-based spatial analysis, researchers and decision-makers can identify flood-prone areas, study flood progression, and determine factors influencing flood severity. This project leverages GIS tools to conduct a comprehensive spatiotemporal analysis of flooding in Kerala over the five-year period from 2018 to 2022.
The objectives of this project include examining flood-affected areas, identifying patterns and trends, and assessing the factors contributing to recurrent flooding. This analysis not only provides insights into the spatial distribution of flood events but also enables an understanding of their temporal variations, helping inform proactive management strategies and risk mitigation approaches. This project aims to contribute valuable findings that can support policymakers and stakeholders in enhancing Kerala's resilience to future flooding events.
1.1 OBJECTIVES
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To map flood-affected areas in Kerala from 2018 to 2022
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To analyze the spatial and temporal patterns of flooding
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To assess the contributing factors to flooding in Kerala
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To identify flood-prone zones and vulnerability hotspots
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To evaluate the impacts of floods on local communities and infrastructure
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To provide recommendations for flood management and mitigation strategies
1.2 Study Area: Kerala India
The study area for this project is the state of Kerala, located along the south- western coast of India. Kerala spans an area of approximately 38,863 square kilometers and is bordered by the Western Ghats to the east and the Arabian Sea to the west. Known for its unique geography, Kerala has a diverse topography, ranging from high-altitude Mountains in the east to low-lying coastal plains in the west. The state's landscape includes extensive river systems, wetlands, and backwaters, which play a vital role in its hydrology and make it particularly vulnerable to monsoon-related flooding. Kerala's climate is primarily influenced by the southwest monsoon, which occurs from June to September, bringing heavy rainfall that can trigger floods, landslides, and other hydrological events.
This study focuses on analyzing flood-prone areas across Kerala using GIS data from the years 2018 to 2022. It will cover urban and rural regions alike, aiming to identify areas of recurring flooding and assess the impacts on affected communities. By examining patterns and trends in these flood events, this study seeks to understand the spatial distribution and the contributing factors that make certain areas more susceptible to flooding.
[Fig No 1: Shows study area Kerala]
LITERATURE REVIEW
2.1 Flooding Patterns and Contributing Factors
Several studies have explored the hydrological and meteorological factors contributing to flooding in Kerala. Research indicates that Kerala’s geographical characteristics, such as its mountainous terrain, dense river networks, and proximity to the coast, contribute to rapid runoff and susceptibility to flash floods (Kumar et al., 2019). The Western Ghats play a significant role in capturing and channeling heavy monsoon rainfall, often leading to overflow in river basins (Ramakrishnan et al., 2020).
2.2 GIS and Remote Sensing in Flood Risk Analysis
GIS and remote sensing techniques have proven invaluable in flood risk mapping, assessment, and monitoring. Several studies have used satellite imagery and GIS- based hydrological models to map flood-prone zones and analyse flood extent (Singh et al., 2018). Remote sensing also allows real-time flood monitoring, which enhances early warning capabilities (Chowdary et al., 2020).
2.3 Spatiotemporal Analysis of Floods
Studies have also emphasized the importance of spatiotemporal analysis in understanding flood dynamics. Spatiotemporal analysis helps identify patterns and changes in flood-prone areas over time, thereby improving flood prediction accuracy and management (Roy & Saha, 2021).
2.4 Climate Change and Extreme Weather Events
Research indicates that climate change is a significant driver behind the increasing frequency and intensity of floods worldwide, including in Kerala. Changes in monsoon patterns, increased precipitation, and rising sea levels are expected to intensify flooding (Rajeevan et al., 2018).
RESULT AND ANALYSIS
LULC changes (2017-2022)
The maps below illustrate the Land Use and Land Cover (LULC) changes in Kerala from 2017 to 2022. Significant transformations are evident during this six- year period, with an increase in built-up areas and a corresponding decrease in vegetation cover. The LULC maps were generated using the supervised classification method, categorizing the region into distinct classes such as vegetation, water bodies, built-up areas, and bare ground, among others.
[Map: LULC maps for 2017-2018]
Rainfall analysis
Over the past five years, Kerala has experienced severe rainfall events. The state's unique geographic features, with the Western Ghats on the east and the Arabian Sea on the west, make it highly susceptible to intense monsoon activity each year. Rainfall data for Kerala, sourced from the India Meteorological Department (IMD), has been processed and is presented here for analysis. During the monsoon months of July to September, rainfall varied between 6 mm and 14 mm annually.
DEM data Analysis
Digital Elevation Model (DEM) data was processed to derive key topographical features, including elevation, slope, and stream order for the 44 rivers in Kerala. These parameters, combined with Land Use and Land Cover (LULC) data and Synthetic Aperture Radar (SAR) data, provide valuable insights into identifying flood-prone areas across the state.
[Map: Maps for stream order]
SAR data analysis
SAR data for the monsoon periods of the past five years in Kerala was processed and compared with post-monsoon data from 2017. The analysis reveals that a significant number of areas have been affected by flooding, with many of these being densely populated human settlements.
[Map: Flood analysis maps for 2017 and 2018]
Comparison between post-Monsoon and Monsoon
District wise flood Analysis
Flood data was analysed for each district, revealing that most flood-affected areas are densely populated human settlements. The central region of Kerala, comprising Ernakulam, Thrissur, Alappuzha, and Kottayam, is particularly vulnerable to flooding. This region includes some of Kerala's most developed cities and is traversed by numerous rivers, which contributes to the heightened flood risk.
The visual data highlights human living areas in red and vegetation in green. Distinct stream-like features in other colors represent flood-affected regions, many of which overlap with human settlements. The analysis clearly shows that during the 2018 floods, the central part of Kerala experienced the most severe impact.
CONCLUSION
This study analysed the spatiotemporal patterns of flooding in Kerala over the past five years (2018–2022) using GIS tools and integrated datasets, including LULC, DEM, SAR, and rainfall data. The results reveal significant changes in land use, with an increase in built-up areas and a corresponding reduction in vegetation cover. The central regions of Kerala, particularly Ernakulam, Thrissur, Alappuzha, and Kottayam, were identified as the most flood-prone, primarily due to their dense river networks, high population density, and extensive urban development.
The study highlights the critical role of topographical features such as elevation and slope, combined with intense monsoon rainfall, in exacerbating flooding in these areas. Furthermore, the overlap of flood-affected zones with human settlements underscores the urgent need for sustainable urban planning and effective flood management strategies.
This analysis provides valuable insights into flood-prone regions and the factors contributing to recurrent flooding in Kerala. These findings can aid policymakers and planners in implementing targeted mitigation measures, improving flood preparedness, and promoting long-term resilience against such disasters. Future studies can enhance this work by incorporating real-time flood data and exploring the socio-economic impacts of flooding in more detail.
SUGGESTIONS
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Strengthen Flood Management Infrastructure: Upgrade drainage systems in urban areas to handle intense rainfall. Construct and maintain levees, embankments, and check dams in vulnerable regions.
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Integrated Watershed Management: Develop strategies to conserve upstream watersheds, which play a vital role in regulating water flow.
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Improved Urban Planning: Implement sustainable urban planning practices to manage rapid urbanization. Restrict construction in flood- prone areas and establish green buffer zones along riverbanks to reduce flood impact.
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Community-Based Flood Mitigation: Involve local communities in flood risk assessments and disaster preparedness programs. Promote awareness campaigns about flood-prone areas and emergency response measures.
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Leverage GIS and Remote Sensing for Real-Time Monitoring: Establish a real-time flood monitoring and early warning system using GIS and remote sensing tools. Integrate historical flood data with current meteorological data to improve forecasting accuracy.
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Enforce Land Use Regulations: Strengthen enforcement of land use and zoning regulations to prevent encroachment into wetlands and floodplains.
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Policy and Governance: Formulate and implement a comprehensive flood management policy specific to Kerala's geographical and climatic conditions.
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Research and Development: Encourage further studies on the socio- economic impacts of flooding in Kerala. Explore innovative solutions, such as rainwater harvesting and nature-based flood defenses, to minimize flood risks.
REFERENCES
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Kumar, P., Sharma, R., & Verma, S. (2019). The influence of geographical features on flood susceptibility: A case study of Kerala. Journal of Hydrology and Geomorphology, 12(3), 112–125.
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National Remote Sensing Centre (NRSC), Indian Space Research Organisation (ISRO), & Department of Space. (2022). Flood Affected Area Atlas of India (1998-2022): Satellite-Based Study.
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Rajeevan, M., Unnikrishnan, C. K., & Preethi, B. (2018). Monsoon variability and extreme rainfall events in India. Climate Dynamics, 52, 733–749.
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Chowdary, V. M., Jha, M. K., & Mal, B. C. (2020). Application of GIS in flood risk management. International Journal of Hydrology, 14(2), 112– 125.
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Kumar, K. P., & Ramakrishnan, V. (2019). Role of Western Ghats in influencing Kerala's flood dynamics. Geography Review, 22(6), 56–62.
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Singh, N., & Roy, P. (2018). Remote sensing applications for flood risk assessment: Case studies from India. Earth Observation Research, 19(3), 211–223.