‘Goa’s coast least hit by erosion’

Panaji: Goa features as the state which has the lowest percentage (17.39%) of its shore length under erosion and the highest percentage (52.37%) of a stable shoreline when compared to 11 maritime states and Union territories in the country according to a study ‘Assessment of Coastal erosion along the Indian coast on 1:25,000 scale using satellite data of 1989-1991 and 2004-2006 time frames’ published in the latest edition of Current Science a fortnightly journal published in collaboration with the Indian Academy of Sciences.
The study’s results indicate that 3,829km (45.5%) of India’s 8,414km coastline on either side of the Indian peninsula excluding the mouth of estuaries, rivers and creeks, is under erosion, 3,004km (35.70%) is getting accreted and 1,580km (18.78%) of the coast is more or less stable.
The state with the highest percentage of its shoreline under erosion is Nicobar Islands (88.7%) while that with the lowest percentage of its shoreline under erosion is Goa (17.39%).
“The cause of severe erosion along Nicobar coast is probably due to the Indian Ocean tsunami of December 2004. In many other parts of the Indian coast, coastal erosion occurs due to the construction of damns in catchment areas of rivers and developmental activities such as construction of ports/fishing harbours/jetties. The analysis shows that the Indian coast has lost a net area of about 73 sq km during 1989-1991 and 2004-2006 time frame,” the study states.
The shoreline changes for the time frame 1989-2006 were mapped for the entire Indian coast based on multi date remote sensing data in GIS environment on the recommendation of the coastal protection and development advisory committee, an apex body concerned with planning of coastal protection measures at the national level in India.
The data will help plan for sustainable development along India’s coast.
Goa also fares better than other states and Union territories with the highest percentage (52.37%) of a stable coastline followed closely by West Bengal, Gujarat and Andhra Pradesh.
The coast along Kerala, Odisha, Maharashtra, Tamil Nadu and Puducherry, Nicobar Islands, Andaman Islands and Lakshadweep Islands show less than 10% as stable in general.
“Coastal habitats such as mangroves, coral reefs and lagoons are recognized as the best defence against sea storms and erosion, deflecting and absorbing much of the energy of the sea storms. Therefore, it is important to maintain these natural habitats for shore protection as well as for environmental conservation. Human activities that remove or degrade protective landforms – removing beach sands, weakening coral reefs, bulldozing dunes or destroying mangroves, swamps, diminish the degree of natural protection. Human interference with natural coastal processes such as the building of groins, jetties, breakwaters, sea walls, artificial dunes and other structures is occasionally successful but in some cases it causes considerable coastal erosion. These have had mixed successes and often cause additional problems in adjacent areas,” the study authored by experts from the Space Applications Centre, Indian Space Research Organization and Central Water Commission, ministry of water resources stated.
Former NIO scientist Dr Antonio Mascarenhas who has been studying Goa’s coast for many years now says it is heartening to note that the coast of Goa is in a significantly good shape. “Since it is an all India study the authors are unable to point out the exact causes of erosion which of course needs a site specific approach. In the case of unprecedented erosion caused due to the grounding of River Princess, the rate of erosion that occurred was 85 metres in 11 years which is around 7.5 m per year, the highest ever reported along the west coast of India. This was a case of ‘rapid short term coastal erosion’ due to man-made impediment that blocked sediment transport with consequent starvation of the Sinquerim coast.”
Since the study is primarily based on the shift in HTL, this proves that the HTL of Goa has not shifted much, he says. “Coastal erosion in Goa is almost exclusively anthropogenic where sand dunes are the most impacted by human activities. Beach shacks have taken a heavy toll on the dune line and consequently the HTL. Colva and Morjim among others are classic examples where the HTL is retreating exclusively due to wrong location of beach shacks.”
Therefore he says it should be our endeavour to see that the HTL does not shift inland. “On the contrary we should strive to see that the dune line is pushed further towards the sea by building fatter vegetated sand dunes. That is the essence of coastal management.”