An analysis of problems related to dredging in a coral atoll: Kavaratti,Lakshadweep, Indian Ocean

Detailed survey on various aspects has indicated the presence of calcareous sands in the lagoons of Lakshadweep (Arabian Sea) suitable for a number of industries. No data are available about the effect of mining the deposits on these atolls. This paper attempts to analyze the data collected in studying the channel that has been dredged in connection with development of the harbor at Kavaratti lagoon Maximum depth in the lagoon is 3 m Outside the depth increases rapidly within a short distance of about 100 m Sediment in the lagoon is derived from the destruction of the reefs and consists of corals, halimeda, molluscan shells, foraminifers, and red algae Presently sands are being dredged from the lagoon and dumped in the sea and these sands are lost as there is a steep slope outside A study of shoreline records for the beaches adjacent to the dredging site shows that the shoreline is an area of accretion. It is quite possible that removal of 1 or 2 meters of sands from the lagoon floor will not affect the equilibrium if the reef is not disturbed Dredging of coral sands for different purposes is known from Fiji, Johnson Island, offshore Apia and no adverse effect has been noticed Removal of limited quantity of sands is recommended, since in a closed system of such atolls like Kavaratti there is always a surplus of sediment transported to the deep sea. The surplus sediment opens the way to sediment dredging. However, reef areas should not be disturbed since the reef is the most important sediment-generating site Studies on growth rate, currents, tides, and bathymetry should be continued to detect the adverse effect simultaneously with dredging The views expressed in this paper are entirely those of the author and no organization is responsible for them.