Published: 2nd May, 2022
Context
27% of coastline expanded between 1990 and 2018, according to a report by Union Ministry of Earth Sciences.
About
Coastlines in India
- Length of the coastline of India including the coastlines of Andaman and Nicobar Islands in the Bay of Bengal and Lakshadweep Islands in the Arabian Sea is 7517 km.
- Length of Coastline of the Indian mainland is 6100 km which is surrounded by the Arabian Sea in the west, Bay of Bengal in the east, and the Indian Ocean in the south.
What is the need for prevention of Coastal Erosion?
- The coastal regions where land and water meet are ecologically dynamic and sensitive regions, as marine and coastal ecosystems continuously impact on each other.
- These regions have a rich ecosystem such as mangroves, water bodies, seaweeds coral reefs, fisheries and other marine life, and other coastal and marine vegetation.
- These ecosystems protect the region from saline winds, cyclones, tsunami waves etc., promote carbon sequestration and promote biodiversity as well as provide raw materials for a number of manufacturing activities. Hence, this is an alarming situation for us to overcome from the coastal erosion.
Causes of Coastal Erosion
- Wave energy is considered to be the primary reason for coastal erosion.
- Natural hazards like cyclones, thermal expansion of seawater, storm surges, tsunami etc due to the melting of continental glaciers and ice sheets as a result of climate change hamper the natural rhythm and precipitate erosion.
- Strong littoral drift resulting in sand movement can also be considered as one of the major reasons for coastal erosion.
- Dredging, sand mining and coral mining have contributed to coastal erosion causing sediment deficit, modification of water depth leading to longshore drift and altered wave refraction.
- Coastal erosion has been sparked by fishing harbours and dams constructed in the catchment area of rivers and ports reducing the flow of sediments from river estuaries.
- Heavy rainfall can enhance the saturation of soils, with high saturation leading to a reduction in the soil’s shear strength, and a corresponding increase in the chance of slope failure (landslides).
Rainfall Intensity and Runoff
- The impact of raindrops will break up the soil and water build-up will create runoff, taking sediment with it
Why erosion in eastern coast more than western coast?
- The eastern coast underwent more erosion due to frequent cyclonic activities from Bay of Bengal in the past three decades, compared to the western coast, which remained largely stable.
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