The National Centre for Coastal Research (NCCR) in its latest 2022 publication of the Assessment of Shoreline Changes analysed over 6,907 kms of coastline of the mainland between 1990 and 2018. According to the data, between 1990 and 2018, 33.6% of the country’s coastline was under varying degrees of erosion, 26.9% was accreting and the remaining 39.5% was in a stable state. Greater Coastal Erosion was observed on the East Coast of India.
India’s extensive coastline, spanning about 7,500 kilometres, is a treasure trove of biodiversity and a hub of economic activity. However, it grapples with the pressing challenge of coastal erosion. Not just in India, coastal erosion is receiving increasing global attention due to its significant impact on coastal communities, economies, and ecosystems. In this story, we look at what the phenomenon is, its extent in India, and the mitigation measures taken.
Coastal erosion is the gradual wearing away or removal of land, sediment, or rock along coastlines. It is a natural phenomenon caused by waves, currents, tides, and weather conditions over a period of time. However climate change and anthropogenic or human activities have accelerated erosion rates in many coastal areas. Human activities such as infrastructure development near coastlines, extensive sand extraction for construction, mining, and alteration of natural coastline disrupt the natural flow of sediment, compromising the stability of coastlines and accelerating the process of erosion. Its rate and extent vary from place to place.
Billions of people are vulnerable to coastal erosion globally
The impact of coastal erosion extends beyond mere land loss. It has significant impacts on ecosystems, economies, communities, and infrastructure. To illustrate, in the United States, the average annual loss in coastal property is about USD 500 million. According to the United Nations Environment Programme (UNEP), about 37% of the world’s population lives within 100 km of the coast, at a population density twice the global average which indicates how billions are vulnerable to the phenomenon and places stress on the need for immediate measures to address the same.
India’s coastline is spread across 9 states and 2 Union Territories on the mainland and two Islands. The population in the 66 coastal districts was 171 million, accounting for nearly 14% of the total population of India, according to the 2011 Census.
The National Centre for Coastal Research (NCCR) is an attached office of the Ministry of Earth Sciences that has been monitoring the shoreline changes in mainland India since 1990 using remote sensing data, GIS mapping techniques, and field surveys. In its latest 2022 publication, National Assessment of Shoreline Changes along Indian Coast, 2022 Volumes 1&2, over 6,907 kms of coastline of the mainland has been analysed for the period from 1990 to 2018. The results are classified into three categories- erosion, stable and accretion. The shoreline change rates have been classified into seven classes as given in the following table.
The data on the change in shoreline as per the 2022 report and the 2018 report (covering the period from 1990 to 2016) from Dataful has been used in this story.
According to the data, between 1990 and 2018, 33.6% of the country’s coastline was under varying degrees of erosion, 26.9% was accreting and the remaining 39.5% was in a stable state. Out of the 6,907 kms of the coast in the mainland, about 2,318 km was under erosion and 1,855 km faced accretion. Compared to the previous report covering the period from 1990 to 2016, the share of shoreline facing accretion has declined from 29% while that under erosion has increased marginally by 0.6%.
More than half of the coastline in West Bengal and Puducherry underwent erosion between 1990 & 2018
State-wise data reveals that more than 60% of the coastline of West Bengal faced erosion in the 28-year period. This was followed by Puducherry with 56.2%. While more than half of the coastline in West Bengal and Puducherry faced erosion, the share was more than 40% in Kerala and Tamil Nadu with 46.4% and 42.7%, respectively. 34.6% of the coastline in Daman & Diu, 28.7% in Andhra Pradesh, 27.6% in Gujarat, 25.6% in Odisha, 25.5% in Maharashtra, 23.7% and 19.2% in Goa had undergone erosion between 1990 and 2018.
On the other hand, nearly 51% of the coastline in Odisha expanded or underwent accretion followed by Andhra Pradesh with 49.6%. The share of coastline that underwent accretion in descending order is Karnataka (26.2%), West Bengal (25.2%), Tamil Nadu (23.8%), Kerala (22.8%), Gujarat (19.4%), Goa (13.7%), Daman & Diu (11.7%), Puducherry (10.6%) and Maharashtra (10%).
More than half the coastline was stable in almost all the states and UTs on the west coast, except Kerala while it varied from 14.3% in West Bengal to about one-third in Tamil Nadu & Puducherry on the east coast.
In essence, the data indicates that the west coast is more stable than the east coast. Out of the total 3,762.62 km long coastline on the west coast, a total of 1,113.27 km had undergone erosion, roughly about 30%. On the east coast, 1,205.4 km faced erosion of the total coastline of 3,144.56 km, which is about 38%. Another 690.5 km of the coastline on the west coast and 1,164.5 km along the east coast expanded. This is about 18% and 37% of the total length of the west and east coast, respectively. The length of coastline that underwent accretion is much lower than the eroded length across all the states & UTs except Karnataka on the west coast and Andhra Pradesh and Odisha in the east coast.
11% of the coastline in the east coast faced high erosion compared to 1% in the west coast during 1990 to 2016
Data on the state-wise length of coastline by status of erosion and accretion is available for the period from 1980 to 2016. According to this data, 48% of the coastline was stable along the west coast when compared to 28% along the east coast. Only 1% of the coastline along the west coast had undergone high erosion, 2% faced moderate erosion, and 24% faced low erosion. In contrast, 11% of the coastline on the east coast faced high erosion, 5% faced moderate erosion, and 22% faced low erosion. Accretion was high along 8% of the coastline in the east and 2% in the west.
The data from the report indicates that the level of erosion and accretion is highly varied along the shoreline on the east and west coast. Even across states, there is considerable difference. This difference can be attributed to natural causes or human interventions. It should be noted that the reports have not considered the coastline of the island territories which are highly vulnerable to rising sea levels and changing coastlines.
Measures of the Central Government
The Government of India has implemented measures like Coastal Regulation Zone (CRZ) Guidelines and Mangrove Initiative for Shoreline Habitats & Tangible Incomes (MISHTI), to address coastal erosion and manage coastal zones sustainably. The National Disaster Management Authority has prepared a draft policy on “Mitigation and Rehabilitation measures for people displaced by Coastal and River Erosion” to deal with the extensive displacement of people caused by coastal and river erosion following the XVth Finance Commission’s recommendations. Further, the environment ministry has delineated the hazard line for the entire coast of the country which indicates the changes in shoreline, including sea level rise due to climate change. This line is to be used by agencies in the coastal states as a tool for disaster management including planning of adaptive and mitigation measures.
Featured Image: Coastal Erosion
