Directional wave measurements off Navinal, Gulf of Kachchh, India

Abstract

Results of directional wave measurements carried out off Navinal, Gulf of Kachchh representing pre-monsoon and southwest monsoon wave conditions are presented. Maximum wave height encountered during pre-monsoon and southwest monsoon is 1.36 and 1.54 m respectively. Though large wave heights of the order of 3 to 4m exist elsewhere along the west coast of India during these seasons, Navinal seems to be a less wave active zone because of its geographical location. Maximum wave energy is centred around 3 to 5 sec and shows that seas prevail over swells. Occurrence of a few long period waves, of the order of 20-25 sec, has been noticed during pre-monsoons but not during the southwest monsoon. Spectral modification caused to the waves has been traced. An exercise was carried out to see if any relationship exists between these long period waves and various stages of tides, but no pattern could be noticed. As this study is meant for coastal development activities, occurrence of cyclone is also looked into, but not a single cyclone has hit Navinal directly in the last 87 years