Browsing by Author "Gowthaman, R."

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Land use/land cover changes around Rameshwaram Island, east coast of India
(2014) Gowthaman, R.; Dwarakish, G.S.; Sanilkumar, V.
Land-use/land cover changes are studied using the Indian Remote Sensing satellite (IRS-1C, IRS-P6) Linear Image Self-scan Sensor (LISS) III data of 1998 and 2010. Coastal land use categories such as sand, vegetation, coral reef and water have been identified using interpretation keys. Results of land-use/land cover assessment based on visual interpretation are presented. The study indicates water body of 178 and 177 km2, sand features of 32 and 32 km2, vegetation of 28 and 35 km2 and coral reef of 5 and 6 km2 respectively. 2014, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.
Land use/land cover changes around Rameshwaram Island, east coast of India
(National Institute of Science Communication and Policy Research, 2014) Gowthaman, R.; Dwarakish, G.S.; Sanilkumar, V.
Land-use/land cover changes are studied using the Indian Remote Sensing satellite (IRS-1C, IRS-P6) Linear Image Self-scan Sensor (LISS) III data of 1998 and 2010. Coastal land use categories such as sand, vegetation, coral reef and water have been identified using interpretation keys. Results of land-use/land cover assessment based on visual interpretation are presented. The study indicates water body of 178 and 177 km2, sand features of 32 and 32 km2, vegetation of 28 and 35 km2 and coral reef of 5 and 6 km2 respectively. © 2014, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.
Nearshore waves and longshore sediment transport along Rameshwaram island off the east coast of India
(2015) Gowthaman, R.; Sanil, Kumar, V.; Dwarakish, G.S.; Shanas, P.R.; Jena, B.K.; Singh, J.
Wave-induced Longshore Sediment Transport (LST) play an important role in the dynamics of the Dhanushkodi sandspit located southeast of Rameshwaram. The LST along the Dhanushkodi coast is studied based on data collected simultaneously in Gulf of Mannar (GoM) and Palk Bay (PB) using directional waverider buoys. The numerical model REF/DIF1 was used to calculate the nearshore waves and the LST rate was estimated using three different formulae. The model validation was done based on the measured nearshore waves using InterOcean S4DW. Numerical model LITPACK was also used for simulating non-cohesive sediment transport and the LITLINE module was used to study the shoreline evolution over 5 years. Low net annual LST along PB (~ 0.01 106 m3) compared to the GoM region (0.3 106 m3) were due to the weak waves. Accretion in the region led to growth of the Dhanushkodi sandspit by 65 m during the period 2010-2015. SNAK, 2015.
Nearshore waves and longshore sediment transport along Rameshwaram island off the east coast of India
(Society of Naval Architects of Korea jnaoe@jnaoe.org, 2015) Gowthaman, R.; Sanil Kumar, V.; Dwarakish, G.S.; Shanas, P.R.; Jena, B.K.; Singh, J.
Wave-induced Longshore Sediment Transport (LST) play an important role in the dynamics of the Dhanushkodi sandspit located southeast of Rameshwaram. The LST along the Dhanushkodi coast is studied based on data collected simultaneously in Gulf of Mannar (GoM) and Palk Bay (PB) using directional waverider buoys. The numerical model REF/DIF1 was used to calculate the nearshore waves and the LST rate was estimated using three different formulae. The model validation was done based on the measured nearshore waves using InterOcean S4DW. Numerical model LITPACK was also used for simulating non-cohesive sediment transport and the LITLINE module was used to study the shoreline evolution over 5 years. Low net annual LST along PB (~ 0.01×106 m3) compared to the GoM region (0.3×106 m3) were due to the weak waves. Accretion in the region led to growth of the Dhanushkodi sandspit by 65 m during the period 2010-2015. © SNAK, 2015.
Sand spit and shoreline dynamics near Terekhol River mouth, Goa, India
(2014) Rajasekaran, C.; Kumar, S.J.; Gowthaman, R.; Jishad, M.; Yadhunath, E.M.; Pednekar, P.S.
Evolution of shoreline and sand spit at the mouth of the Terekhol River, near Keri beach, located in the Indian state of Goa has been investigated. From the analysis of the data collected, the shoreline oscillation (accretion & erosion) is seasonal up to 2010. A sand spit of 2 m height has been stabilized in 2012 during monsoon in the southern bank of the river which obstructs the natural flow of the river and also hindrance to the ferry transport system. This leads to the unbalanced scenario between the sediment discharge from the river and the littoral transport. Around 2 km stretch of shoreline is under severe erosion in which a stretch of 500 m of sea wall is completely damaged. Sand spit present in the northern part of the shoreline plays a vital role in the shoreline oscillation. Tetrapods were placed recently to protect the eroding part of the coast. Due to the unbalanced littoral movement, the erosion is still persisting and started damaging the new tetrapod protective measure. 2014, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.
Sand spit and shoreline dynamics near Terekhol River mouth, Goa, India
(National Institute of Science Communication and Policy Research, 2014) C, C.; Kumar, S.J.; Gowthaman, R.; Jishad, M.; Yadhunath, E.M.; Pednekar, P.S.
Evolution of shoreline and sand spit at the mouth of the Terekhol River, near Keri beach, located in the Indian state of Goa has been investigated. From the analysis of the data collected, the shoreline oscillation (accretion & erosion) is seasonal up to 2010. A sand spit of 2 m height has been stabilized in 2012 during monsoon in the southern bank of the river which obstructs the natural flow of the river and also hindrance to the ferry transport system. This leads to the unbalanced scenario between the sediment discharge from the river and the littoral transport. Around 2 km stretch of shoreline is under severe erosion in which a stretch of 500 m of sea wall is completely damaged. Sand spit present in the northern part of the shoreline plays a vital role in the shoreline oscillation. Tetrapods were placed recently to protect the eroding part of the coast. Due to the unbalanced littoral movement, the erosion is still persisting and started damaging the new tetrapod protective measure. © 2014, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.
Surfzone currents at candolim and Miramar beaches of Goa, India: Measurements and comparisons
(2014) Yadhunath, E.M.; Seelam, J.K.; Jishad, M.; Gowthaman, R.; Rajasekaran, C.; Pednekar, P.S.
Measurements in the surfzone current are often carried out using Acoustic Doppler Velocimeters, Electromagnetic current meters, as well as visual observations based on floats. A simple approach is used to install an Aanderaa current meter in water depths less than a meter and the surfzone currents are measured for a period of about 2 hours during a rising tide. Surfzone wave heights and tide were also simultaneously measured and used to compute wave induced currents based on appropriate equations. The obtained current velocity compared with measured RCM data. Measurements were carried out separately at two beaches (Candolim and Miramar) which have varying topography and different surfzone conditions. 2014, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.
Surfzone currents at candolim and Miramar beaches of Goa, India: Measurements and comparisons
(National Institute of Science Communication and Policy Research, 2014) Yadhunath, E.M.; Seelam, J.K.; Jishad, M.; Gowthaman, R.; C, C.; Pednekar, P.S.
Measurements in the surfzone current are often carried out using Acoustic Doppler Velocimeters, Electromagnetic current meters, as well as visual observations based on floats. A simple approach is used to install an Aanderaa current meter in water depths less than a meter and the surfzone currents are measured for a period of about 2 hours during a rising tide. Surfzone wave heights and tide were also simultaneously measured and used to compute wave induced currents based on appropriate equations. The obtained current velocity compared with measured RCM data. Measurements were carried out separately at two beaches (Candolim and Miramar) which have varying topography and different surfzone conditions. © 2014, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.
Surfzone Wave Characteristics during Flood Tide on the Central West Coast of India
(2015) Seelam, J.K.; Jishad, M.; Yadhunath, E.M.; Rajasekaran, C.; Gowthaman, R.; Pednekar, P.S.; Luis, R.; Mehra, P.
Surfzone wave characteristics, measured using a wave and tide gauge (WTG) during a flood tide, were studied at three different beaches having different nearshore slopes. The spectral wave characteristics viz., wave-height and mean wave period were estimated considering different sample sizes. Inter-comparisons of wave climate between each of three beaches for a similar tide level are presented. The wave-height and mean wave period values obtained from the wave analysis for each of the record using waves by wave method show that surfzone wave-height increased with time during a flood tide and the mean wave period decreased with time up to mid tide and then increased during the rest of the measurement period at Keri and Miramar beaches. At Candolim, the reversing trend of mean wave period increase is observed to occur much before reaching the mid tide level. The surfzone waves during a flood tide indicated that the wave-heights increased with time while the mean wave period showed a decreasing trend in general. The variation of breaker index showed a decreasing trend from low tide to high tide ranging between 0.45 and 0.23. The surf similarity parameter estimated corroborates with the visual observations. 2015 World Scientific Publishing Company.
Surfzone Wave Characteristics during Flood Tide on the Central West Coast of India
(World Scientific Publishing Co. Pte Ltd michael.wagreich@univie.ac.at, 2015) Seelam, J.K.; Jishad, M.; Yadhunath, E.M.; C, C.; Gowthaman, R.; Pednekar, P.S.; Luis, R.; Mehra, P.
Surfzone wave characteristics, measured using a wave and tide gauge (WTG) during a flood tide, were studied at three different beaches having different nearshore slopes. The spectral wave characteristics viz., wave-height and mean wave period were estimated considering different sample sizes. Inter-comparisons of wave climate between each of three beaches for a similar tide level are presented. The wave-height and mean wave period values obtained from the wave analysis for each of the record using waves by wave method show that surfzone wave-height increased with time during a flood tide and the mean wave period decreased with time up to mid tide and then increased during the rest of the measurement period at Keri and Miramar beaches. At Candolim, the reversing trend of mean wave period increase is observed to occur much before reaching the mid tide level. The surfzone waves during a flood tide indicated that the wave-heights increased with time while the mean wave period showed a decreasing trend in general. The variation of breaker index showed a decreasing trend from low tide to high tide ranging between 0.45 and 0.23. The surf similarity parameter estimated corroborates with the visual observations. © 2015 World Scientific Publishing Company.
Waves in Gulf of Mannar and Palk Bay around Dhanushkodi, Tamil Nadu, India
(2013) Gowthaman, R.; Sanil, Kumar, V.; Dwarakish, G.S.; Mohan, S.S.; Singh, J.; Ashok, Kumar, K.
Surface wave characteristics around Dhanushkodi are studied based on the measured data in the Gulf of Mannar and in the Palk Bay. Wave spectra are mainly double-peaked in the Gulf of Mannar and singlepeaked in the Palk Bay. High waves (maximum wave height up to 5.4 m) are observed in the Gulf of Mannar compared to the Palk Bay (maximum wave height is 3.6 m). Wave heights are more in the Gulf of Mannar during the southwest monsoon period and the waves are from south-southwest. In the Palk Bay, high waves are found during the northeast monsoon period. Swells dominate the Gulf of Mannar, except during the southwest monsoon period, whereas wind seas exist in the Palk Bay as distant swells cannot reach the bay due to the protection by Indian peninsula and northern extremity of Sri Lanka. Influence of cyclone Laila is observed during the study period in both the Gulf of Mannar and the Palk Bay.
Waves in Gulf of Mannar and Palk Bay around Dhanushkodi, Tamil Nadu, India
(2013) Gowthaman, R.; Sanil Kumar, V.; Dwarakish, G.S.; Mohan, S.S.; Singh, J.; Ashok Kumar, K.
Surface wave characteristics around Dhanushkodi are studied based on the measured data in the Gulf of Mannar and in the Palk Bay. Wave spectra are mainly double-peaked in the Gulf of Mannar and singlepeaked in the Palk Bay. High waves (maximum wave height up to 5.4 m) are observed in the Gulf of Mannar compared to the Palk Bay (maximum wave height is 3.6 m). Wave heights are more in the Gulf of Mannar during the southwest monsoon period and the waves are from south-southwest. In the Palk Bay, high waves are found during the northeast monsoon period. Swells dominate the Gulf of Mannar, except during the southwest monsoon period, whereas wind seas exist in the Palk Bay as distant swells cannot reach the bay due to the protection by Indian peninsula and northern extremity of Sri Lanka. Influence of cyclone Laila is observed during the study period in both the Gulf of Mannar and the Palk Bay.