Flooding remains one of the most recurrent and damaging
natural hazards affecting the low-lying coastal districts of Kerala, with
Ernakulam District experiencing repeated flood events during the southwest
monsoon. Flood susceptibility is an important mission for early warning systems
and emergency services for the prevention and mitigation of future floods. This
study assesses flood susceptibility in Ernakulam District, Kerala, India, using
the Frequency Ratio (FR) model integrated with Geographic Information System
(GIS) techniques. A flood inventory was developed using historical flood
records and satellite-derived data, and six flood-conditioning factors—geology,
land use/land cover (LU/LC), soil, drainage density, rainfall, and slope—were
selected based on their hydrological relevance. Each factor was classified and evaluated
using the Frequency Ratio approach to quantify its contribution to flood
occurrence. Satellite data, including Landsat imagery and ASTER DEM, were used
to generate thematic maps such as land use/land cover, relief, slope, drainage
density, rainfall, soil, and geology.
The results reveal that built-up areas exhibit the highest
flood susceptibility (FR = 4.65), reflecting the combined influence of rapid
urban expansion, impervious surfaces, and inadequate drainage systems. In
contrast, forested areas demonstrate minimal flood susceptibility (FR = 0.17),
highlighting their role in runoff regulation and hydrological stability. Among
the conditioning factors, geology (FR = 7.73) emerged as the most influential
parameter, followed by land use/land cover (FR = 6.90) and soil characteristics
(FR = 6.58), while slope (FR = 1.60) showed comparatively lower control over
flood occurrence. The highest flood susceptibility was associated with the 7–9
rainfall class (FR = 2.93), indicating that areas experiencing intense rainfall
are more prone to flooding despite their smaller spatial coverage. The final
flood susceptibility map categorises the district into low, moderate, high, and
very high susceptibility zones.
The findings confirm that the Frequency Ratio model is an
effective and reliable tool for flood susceptibility assessment in data-scarce
regions. The generated susceptibility map provides valuable insights for
disaster risk reduction, land-use planning, and sustainable flood management,
thereby supporting climate-resilient development strategies in Ernakulam
District. In future, studies should integrate high-resolution temporal data and
climate change projections to enhance the accuracy and reliability of flood
susceptibility assessments.
Author(s) Details
V. V. Neethu
Department of Geography, Indus International School, Bangalore, 562125,
India.
Please see the book here :- https://doi.org/10.9734/bpi/crgese/v6/7160
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