Spits such long and narrow beach features which extend in front of coastal lakes, lagoons, in the direction of dominant winds are consequent long shore drift which is a zigzag long shore current produced by waves under the influence of winds striking a shore obliquely or current. These bars have an open end and are attached to the land on the other side. But the exact manner of spit building is not known. Spits have been found to lengthen as well as shorten during coarse of years. This might be due to change of currents. Spits are likely to come into existence where the currents are tangential to a headland and do not pursue the irregularities of the shore.
According to Lewis, the spits are due to waves coming along long fetch rather than currents and it is the waves of storm periods, which determine the slope of spits. Spits may also extend from two ends towards each other in front of a coastal lake or bay. Their union is checked by the passage of tidal water up and down the opening. In some cases the spits are curved at the distal end probably because of deeper water at that end. In deep water the wave plunges vertically and there is combing down and destruction of beach rather than its deposition. It may also be due to the recession of the coast as a whole where the spit is curved landward.
The curvature is probably also caused by the automatic turning of the waves at the open end of the spit. Some spits are compound with several later extensions near the hooked end. It is believed that each lateral is related to a former seaward position of the spit. As the land receded, the spits migrated landward and their prototypes were demolished leaving only a small curved end. There are notable examples of spit on the western and eastern coasts of India. The spit on the mouth of Chilka Lake is 50 km long with open end in the northeast. Further south-west near Kalingapatnam, there is a 16 km long spit. This appears to have grown from a length of about 12 km in 1915 to 16 km in 1967.
The spit on the east of Kakinada Bay has been growing northward at the rate of 12 km per century. La Fond predicted that the spit would extend northward so much as to convert the bay into a lake in the next 50 years (i.e., about 2015 A.D). This has been due to increased discharge of sediments by the Godavari into the open sea than into the small Kakinada Bay. This riverine sediments has been carried northward by a long shore northerly drift. The spit is curved northwestward at its northern tip. This probably is due to the dominance of the NE Monsoon here in contrast with the coast further north-east where the south-west monsoon is most powerful giving rise to the invariably north-eastward pointing spits in this section under the influence of SW-NE long shore drift. The spit that lies east of the Pulicat Lake on the east coast of India is about 60 km long and is open in the south near Pulicat town. As this opening is an important link between the lake and the open sea it has been kept artificially open otherwise it would have joined the main land and been converted into a bar.
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On the western coast, two spits enclose the Vembanad Lake. That from the north is about 22 km long. That from the south extending northward is 55 km long. Near the point of convergence is the port of Cochin. Near Coondapoor about 90 km north of Mangalore there is an example of a curved spit. This spit is about 3.8 km long joined to the mainland in the south. It curves landward at the northern end. Apart from the above-mentioned spits there are numerous other shorter spits on the eastern and western coasts of India but while the spits on the western coast are frequently ‘double’ or ‘convergent’ type converging from the two ends of the mainland, those on the eastern coast are bannerbank type, i.e., all open in the same direction, i.e., north-east. The ‘double’ type spits were believed by Robinson to be due to the breaching of bars by storm waves. The spits on the west of Vembanad Lake in Kerala are good example of double spits.