Assessing Underwater Noise Levels during Various Port Activities at the Visakhapatnam Channel

Abstract

Transport infrastructure is one of the most important factors for country’s progress or economic growth.  Ports serve as important transportation hubs that facilitate goods movement. Visakhapatnam Port is the second largest port by volume of cargo handled located in the east coast of India. Under the modernization program the port is capable for handling vessels upto 14.5 mby maintenance dredging and some jettiesextension with piling activity. The major activities of the port operation are the vessel handling using tugs and movement of other vessel within the inner harbor of the Visakhapatnam channel. The underwater noise levels of the channel are measured by deploying Omni-directional hydrophone at different location along the channel and the radiated noise levels due to the tug boat operations. The TASCAM data recorder is used to convert the voltage signal to sound file and Fast Fourier Transformation spectral analysis program for post-processing the time and frequency domain spectrum. The tug machinery self-noise indicated a peak amplitude of 157 dB re 1µ Pa at 425 Hz. The jetty modification work recorded the piling activity radiated noise levels as indicated in the spectrogram in the lower frequency of nearly one second duration. The anthropogenic noise due to tugs movement and the piling activity have major influence in increasing the ambient noise of the region. However, there are no evidence of presence any marine mammals getting effected due to the continuous shipping and other activities in the region. The present study shall help to develop measures to reduce the increase in the ambient noise levels of the region due to various anthropogenic sources as part of a major environment impact assessment study for developing a green port. 

Keywords: Port, tug boats, piling and noise levels.