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An attempt has been made to study the impact of sand dredging on water quality of Nethravathi estuary, Mangaluru. The samples were collected from five different identified stations viz S1, S2 and S3 are dredged sites and stations S4 and S5 are un-dredged sites during October 2014 to April 2015. Study revealed that the dredging operation has impact on water quality. Among the water parameters the effects on surface water temperature, pH, dissolved oxygen and salinity were negligible whereas the total suspended solids and turbidity showed higher levels at dredged stations. Further, the results showed reduced Secchi transparency levels at dredged stations. Similarly, the lower concentrations of nutrients at dredged stations due to the indiscriminate removal of sand and organic sediment showed a clear impact of dredging.

Key words: Nethravathi estuary, Sand dredging, Temperature, Salinity, Water quality.