India’s Coastline Recalculated: Methodology, Challenges, and Impact

Context: 

India’s coastline has been revised from 7,561.60 km to 11,098.81 km, marking an increase of 3,537.21 km, or nearly 50%.
This update results from advanced measurement methods and better mapping technology. Understanding the reasons and implications is crucial for policy, security, and planning.

Challenges in Measuring Coastline

• Coastline Paradox: Introduced by Lewis Fry Richardson in the 1950s, it highlights that the length of a coastline varies with the scale of measurement.

• Fractal Nature: Benoît Mandelbrot (1967) found coastlines exhibit fractal-like properties — the more detailed the measurement, the longer the coastline appears.

• Ruler Dependency:

  • A 200 km ruler smooths out small features.

  • A 1 km ruler captures every inlet, creek, and curve.

  • As the ruler gets smaller, the measured length increases.

Reasons for the Increase in India’s Coastal Length

• Change in Calculation Method:

  • Earlier methods used straight-line distances.

  • New method uses a fractal approach, recording every natural feature and curve.

• Higher Map Resolution:

  • Previous data used a 1:4,500,000 scale from the 1970s.

  • Updated data used 1:250,000 scale electronic navigation charts by the Survey of India and National Hydrographic Office (NHO).

• Updated High Water Line:

  • Based on 2011 high tide data.

  • River mouths and creeks were closed at a fixed inland point.

• Inclusion of Offshore Islands:

  • About 1,389 islands/islets not included earlier are now considered.

  • Coastline of each individual island is included in the final measurement.

Revised Coastline Length by Region

• Andaman & Nicobar Islands – 3,083.5 km

• Gujarat – 2,340.6 km

• Tamil Nadu – 1,068.7 km

• Andhra Pradesh – 1,053.1 km

• Maharashtra – 878.0 km

• West Bengal – 721.0 km

• Kerala – 600.2 km

• Odisha – 574.7 km

• Karnataka – 343.3 km

• Goa – 194.0 km

• Lakshadweep Islands – 144.8 km

• Daman & Diu – 54.4 km

• Puducherry – 42.7 km

• Total – 11,098.81 km

The coastline will now be reviewed every 10 years using updated datasets.

Implications of the Updated Coastline

• Maritime Security:

  • A longer coastline demands enhanced maritime surveillance and resource allocation.

• Disaster Preparedness:

  • Helps in better planning for cyclones, sea-level rise, and other coastal hazards.

  • Improves zoning regulations and climate adaptation strategies.

• Exclusive Economic Zone (EEZ):

  • May result in an expansion of marine rights over natural resources like fisheries, oil, and gas.

• Coastal Regulation and Development:

  • Requires updates to CRZ norms and coastal management plans.

  • Affects construction, tourism, and environmental conservation.

• Infrastructure Planning:

  • Enables more accurate planning of ports, industrial zones, and coastal projects.

• Educational Revisions:

  • The revised length must be reflected in textbooks and official documents.