Vizag Port faulty dredging led to erosion of shoreline

By SNV Sudhir

Visakhapatnam, Feb 7, 2014: The Vizag Port is being blamed for the sea surge that damaged the footpath near Kurusura submarine museum on the beach road. Experts warned that if immediate remedial measures were not taken, the entire beach road along with various parks are in danger of being lost to the sea.

Andhra University, Head of Meteorology and Oceanography department, Prof KVSR Prasad, who has done research on beach erosion, says erosion of Visakhapatnam shoreline started way back in 1993 when the island breakwater was constructed for the development of inner harbour.

“The littoral drift during the southwest monsoon got deposited near the entrance channel and the northern beaches were partially cut off from the sand supply. But in the earlier stages the erosion was not significant and was confined only to a short distance northward from the entrance channel. Even in those days the material at the entrance channel used to be dredged periodically and pumped to the northern side and the erosion was under control,” he observed.

Prof Prasad has recently submitted a report on his findings on the recent sea surge to the district administration.

He further said that depending on the erosion, the pumping site used to be shifted suitably to check erosion. But later due to some operational problem, it appears the direct pumping of sand was reduced and instead the sand was dredged and dumped into the sea which was not that much effective, he observed. The dredging and pumping of sand is done by the Visakhapatnam Port Trust (VPT) that manages Vizag Port.  

In the year 1968 the construction of outer harbour was contemplated to handle the increasing shipping traffic. The construction of the north and south break waters was completed by 1975 and the east breakwater was completed by 1976. A sand trap was provided near the south breakwater in addition to a dredging berth and 3 km long pipeline.

“While designing the outer harbour it was suggested that about 0.45 million cubic meters of sand was to be pumped annually to the northern side to protect the northern beaches. By this process it was thought a balance could be achieved between the sand pumped and the sand lost due to erosion. But it appears the balance is a very delicate balance that is easily disturbed especially during cyclone periods. During such periods it is necessary to enhance the beach nourishment by pumping additional sand to the north side,” Prof Prasad pointed.

Most of the states are implementing the construction of seawall/ groins as remedial measures to control coastal erosion in view of their low cost, easy constructions etc.

But most of the areas along the coast are still undergoing extensive erosion exclusively in the coastal regime of Chennai near Ennore, parts of Kerala, Pondicherry, Karnataka, Andhra Pradesh, Odisha and Gujarat due to lack of understanding of the site specific coastal issues.

“The construction of groins will create other problems like rip currents and will destroy the beauty of nature and the sea walls cannot withstand when a wave heights of more than 5m occurs. So, it is advisable to construct offshore submerged breakwaters at around 3-5m depth from our studies. Also, It is necessary that the sounding of the coastal waters has to be taken up more frequently and the changes in the near shore topography be monitored from time to time in order to take timely measures for safeguarding of the beaches,” he added.