Details :

COASTAL EROSION IN ODISHA

Bijay Ketan Patnaik

 

Our state Odisha is situated along the East coast embedded by Bay of Bengal and having a coatline of 480.4 Kms long. This long coast line is interspersed by the compliance of 10 major rivers such as Mahanadi, Brahmani, Baitarani, Suvernarekha, Budhabalanga, Rushikulya etc. falling into the Bay of Bengal and thus creating numerous islands and deltas. The coastal Zone of Odisha spreads over an approximate area of 22,800 sq.kms spanning over the 6 coatal districts of Balasore, Bhadrak, Kendrapara, Jagatsinghpur, Puri and Ganjam.

 

Coastal Erosion

Coastal environment is a complex and dynamic eco-system, where there is a constant interaction going in between land, sea and air culminating in shore line changes. The landward displacement of the shore time caused by the forces of waves and currents is termed as ‘Coastal Erosion’. In fact coastal erosion is the wearing away of the land and the removal of beach on dune sediments how loss of subacrial land inass  into sea on line due to natural process like  wave action, wave current or drainage. Although coastal erosion is a chronic problem, it is very often considered as inevitable along mot open shores as a natural phenomenon. While the effects of waves, currents, tides and wind are primary natural factors that influence the coast profile, various anthropogenic factors also trigger beach erosion. These include construction of artificial structures along the foreshore, mining of beach sand, off shore dredging on building dams across river basins. These developments at times are not compatible with the dynamic nature of shoreline.

 

Problems of Coastal Ecosystem

Because of increasing use of coastal region for developmental purposes like industries, fishing, harbors facility and venerability to natural hazards, sea- level rise, the following changes along the coast line is observed.

a)      Shifting of the shore line

b)     Coastal erosion

c)      Formation of sand bars at in-lets of water body

d)     Change in velocity and currents of coastal water

e)      Littoral drift

f)       On shore/Off shore sediment transport

g)      Sand mining

h)     Siltation

i)        Change in beach profile

 

Erosion along Odisha coast

Coastal areas of Odisha state are potentially vulnerable to accelerated erosion hazards along the 480 km coast line most of the coastal areas including tourist resorts, hotels at puri fishing villages and towns at Gopalpur of Ganjam district, Pentha and Satavaya village of Jagatsinghpur distrit are already threatened by storm flood events and severe coastal erosion. The location of major ecological habitat and delicate systems along the coast, such as the largest rookeries in the world of Olive Redley sea turtles(the extensive sandy beach of Gahirmatha ad Rushikulya) Asia’s largest brakish water lagoon the Chilika lake, Mahanadi delta, the second largest delta in India, extensive mangroves of Bhitarkanika are also threatened time and again from coastal erosion angle.

 

To cite a few examples, the coast close to Pentha Village of ____ district is continuously eroding. In July 2007, the saline embankment was in great danger of collapsing. The continuous buffeting of the shore by the waves along this stretch had resulted in the coast line receding landwards by 200 to 300 meters. The situation of Pentha village was also studied by geological Survey of India, revealing periods of accretion and erosion related in all probability to climate change sea-level fluctuations and human activity. Similarly, panic had gripped the Puri town, a few years ago, when tidal waves washed away not only a part of beach, but also the adjoining stretch of road newly constructed from Palm beach hotel to sterling Resort, violating CRZ norms.

 

In the year 2008, the ingress of sea waters along the tourist highway connecting Puri and Konark the entire belabhumi invited fresh worries. It was debated whether the same would be attributed to after effects of dreadful Tsunami of December 2004? During the year 2008 and 2009, the sea at Gopalpur in Ganjam district was in spate. Due to ingress of sea the lighthouse on the shore , sea ide wall of Obrai Hotel and same building on the shore, sea side wall of Obrai Hotel and same building constructed towards sea ward side were damaged. This phenomenon occurred mostly in pre winter period, just after rains, when sediments are moved offshore by high energy storm waves.

 

Shore line Change Assessment for Odisha Coast

A study on shore line change assessment for Odisha coast was entrusted to Prof. R. Ramesh of Anna University, Chennai, working for MoEF’s National Centre for Sustainable Coastal Management. According to the study report released during April 2011 around 187 kms of 480 km stretch of Odisha coast is exposed to High medium and low type of erosion. This accounts for 36.8 % of the cost line. Out of this 39.3 km i.e. 8.2% was identified as high erosion zone. This is found mostly towards North of Devi  River in Puri/Jagatsinghpur district, north of Balijhari river in Jagatswinghpur district. South of Bitinotia River in Jagatsinghpur district and Bansagarh river in Kendrapara district. High erosion could also be found towards north of Subararekha river in Balasore district. 51.96 km i.e. 10.82% stretch of beach falls under medium erosion zone. The report also indicated that the phenomenon of beach erosion is more pronounced to the north of Gopalpur port and Paradeep port across Jatadhar mouth, to the south of Dhamara and proposed Astaranga port. Medium and lower type erosion is also observed in Puri beach, Konark-Chandrabhaga-Ramachandi beach.

 

Wildlife experts and scientists are more worried about intensive erosion taking place around the mass nesting sites of famous Olive Ridley sea Turtles. Since probably half of the world population of Olive Ridley’s are breeding along the east coast of Odisha, global conservation attention in concentrated here and geomorphological changes of the nesting beaches are monitored regularly. Beach erosion was observed to begin during March and it reached the peak during the month of August. A higher rate of erosion is taking place between Satabhaya and Gahirmatha,  a well known rookery of the endangered turtles in the Kendrpara district. This has resulted in complete annihilation of Nasi I and Nasi II beach and drastic reduction of the beach bordering Wheeler Island. The total beach length here has been reduced to almost 1 kilometer. The beach erosion has also threatened the very existence of strategic Wheeler Island.

 

Wind constantly moves sand along the beach. When this natural event is artificially obstructed by constructing a port then at one side of the port, sand gets accumulated on piled and the other side of beach constantly gets eroded and bare rock get exposed gradually. It is said by experts that the beaches across Satabhaya village of Kendrapara district leading to ingress of sea water into the land mass got eroded after the construction of Paradeep port. Presently there are plans to have ports in all major river mouths of Odisha. Notably among these which may greatly impact sea-turtle congregation areas are the Dhamara port at Dhamara river mouth and Barunei port at Mahanadi river mouth close to either side of Gahirmatha mass nesting beach. Ultimately there will be large scale nest destruction due to beach erosion at Arribada sites and shrinking of the nesting habitats due to erosion of beaches. Port at Astaranga closed to Devi mass nesting beach and port at Gopalpur close to Rushikulya mass nesting beach, may also face similar problem in future. Therefore the wildlife scientist fervently plead for preservation of only 80 kms stretch beach around these three mass nesting sites as ‘No Disturbance Zone’.

 

Conclusion

 Coastal areas are of enormous socio-economic importance, because of both their traditional resources, i.e fish, tourist potential, commercial and residential development as wel as new types of resources such as wave energy, off-shore mining, marine resources. The high economic value of these areas and relative facilities coupled with vulnerability to natural hazards, sea-level rise and various anthropogenic activities not compatible with the dynamic nature of our shore line waves the preservation and management of coastal zone resources, ecologically more important.

 

Former P.C.C.F. (Wildlife)

& Chief Wildlife Warden, Odisha

  

 


Source: ENVIS Centre