The beach, in this area, is a smooth uniformly sloping (Average 1.75) made up of fine grained sand and silt. On the landward side, the beach is bounded by dune cliffs. The shore-line from Mohana to the east in Shankarpur region is relatively stable. In the far-west near the Orissa border it is accretional and muddy. But, the entire strip, where the Digha Township is located, in between, is an eroding type, which is the main concern of this resort. The material of the beach consists of mainly sand mixed with clay and the dune material is made up of fine sand.
The erosion of beach and the shore is due to (a) wind erosion; (b) wave and (c) Storm waves.
During the dry months wind erosion is prevalent. The existence of dunes prevented the blowing of sand inland, but where it is absent; it flows within inland and covers the agricultural fields and local habitat.
Waves, together with litteral current and backwash are constantly causing erosion. The storm waves, though not frequent, may cause severe damage along with high tides, and this occurs one or twice a year.
By studying the Survey of India Maps, dating from 1877 to 1931, it has been found that 970 m. of beach has been eroded during this 88 years at an average of 11 m. per year. Recent study shows that the tendencies of erosion exist in the unprotected area of the beach viz. from Mohana to Jamra Shampur mouza in the east and from Yatranala to Orissa border in the west.
The protected area of Digha Township which is in between these two is saved.
In the survey of IAW. Deptt., Govt. of West Bengal 1983-85 it has been shown that the Western-most area faces maximum lowering of the beach. The construction of sea dyke has not halted the beach-lowering even after the completion of sea dyke, and the erosion is continuing at an average rate of 15-20 cm. per year. The Dyke is entirely a superficial structure without any foundation, residing on beach sand and it cannot hold, a storm wave surge of the dimension of 1943 and the toppling of sea dyke is not ruled out. The lowering of the beach east of Mohana has played havoc to fishing installation in this area, viz. Shankarpur area and the huge investment on fish farming and on the other projects of the Government will become endangered and for this, the area needs immediate protection.