The shoreline between the Subarnarekha and the Rasulpur deltas is characterised by sand dunes and a wide sandy beach. Several small tidal creeks cross the shore, the largest being the Shankapur Creek east of Digha. The outstanding management problems at the moment are related to the erosion of the dune face at Digha, a process that, according to anecdotal evidence probably commenced around 1950 and beach lowering. Before 1960s, there were an accretional zone in New Digha, an erosional zone at old Digha and an accretional zone at Sankarpur Dadanpatrabar region. Recent analysis shows that along Digha Sankarpur coast six contrasting accretional and erosional segments could be identified. Being a popular tourist resort, coastal erosion is therefore a critical issue in coastal zone management in this sector of West Bengal coast.
Sundarban areas inclusive of Sagar
Researchers from School of Oceanography, Jadavpur University undertook a time series analysis of the change in the shape, size and geomorphic features of the islands over a period of 32 years (1969-2001). The important observations regarding the erosion accretion pattern of the island system can be summarized as follows:
- Total erosion over the 30 years time span is estimated to be 162.879 sq.km. Few islands like Lohachara and Bedford (6.212 sq. km.) have already vanished from the map.
- Erosion zones are most prominent among the 12 sea facing southern islands from Sagar to the west to Bhangaduni in the east. The southwestern corners of the islands are particularly susceptible to sustained erosion. Erosion is also seen along the sea facing shoreline that is oblique to the incoming waves.
- The western banks of the inner islands are more vulnerable to erosion than the eastern banks and the rate of retreat of western banks is more severe. Accretion is localized in the inner estuaries particularly along eastern and northern margins and along the coasts of islands trending parallel to the incoming waves. The amount of land accretion over the past 30 years is estimated at 82.505 sq. km.
- Within the island system, the Sagar island has suffered the bulk of erosion with an areal loss of 30 sq. km. with marginal accretion.
The net loss in land area in the eastern part of West Bengal coastal zone is probably due to erosion and/or submergence attributed to sea level rise consequent upon recent climate change and global warming. Therefore, in this sector of West Bengal coast coastal erosion is a key issue in coastal zone management.