Faculty Publications

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On numerical modelling of waves, currents and sediment movement around Gurupur-Netravathi river mouth
(2010) Radheshyam, B.; Rao, S.; Shirlal, K.G.
This paper presents an overview of the investigations that were carried out to understand the coastal process along Bengre and Ullal at the Gurupur-Netravathi River mouth in the west coast of India. This river inlet was facing problems of migration and siltation since several decades and therefore two rubble mound breakwaters were constructed during the year 1994 as an intervention to maintain the inlet mouth. After the construction of these river training jetties, the inlet was stabilized, but severe erosion has been taking place along the Ullal spit on the south side of southern breakwater, since 1996 and heavy accretion on the North of Northern Breakwater along Bengre spit, which is now almost stabilized. This study has been undertaken to understand the hydrodynamics along the beaches adjoining the river mouth. For the present study, various field data was collected for the post monsoon season of 2006. The hydrodynamic (HD), Parabolic mild slope (PMS) and Sediment transport (ST) modules of MIKE-21 software were used to understand the hydrodynamics of the study area. Before the model was made use, it was first validated by using field data to understand the hydrodynamics of the area. Since the field data is of limited duration, data collected from the NMPT wave buoy for an entire year was used for the model simulation. From the studies it was confirmed that current direction and sediment movement follow a similar pattern in monsoon and pre-monsoon and a different pattern during post-monsoon. It is observed that the main cause of erosion is due to direct action of waves on the adjoining beaches of the coast and the beaches in the study area are generally in dynamic equilibrium with a small amount of erosion at Ullal. © 2010 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.
Heterogeneous microbial oceanographic environments: Application of GIS technology in deciphering of microenvironment scenarios off the central west coast of India
(2011) Raghavan, B.R.; Nayak, S.R.; Shylini, S.K.; Deepthi, T.; Sadatipour, S.M.T.; Chauhan, P.; Srinivasakumar, T.; Lotliker, A.; Venkat Reddy, D.; Kumaraswami, M.; Ashwini, S.; Nisaj, M.
In the vast oceanic microbial environment of 2468.83km 2, GIS modeling techniques involving sixty query steps, enabled the deciphering of Microenvironments as low as 1.19km 2 to 38.6 km 2 for the summer of 2004 and in case of summer 2005 where 84 query steps were involved to decipher Microenvironments of 10.55km 2 to 25.94km 2. Thirtythree sampling stations were established between Betul to Ankola off the central west coast of India accounting for a spatial coverage of 2468.83km 2. GIS query-modeling investigation was carried out using spatial layers of depth, optical parameters (k-Irradiance attenuation Coefficient, c-Beam attenuation coefficient), sediment size parameters (Sediment Mean Size and Sediment Sorting) and Benthic Foraminifera Suborders (Rotaliina, Textulariina, Miliolina, Lagenina). Foraminifera have been used as a surrogate parameter. However, any microbial parameter could proxy for foraminifers providing for the numerical deciphering of microenvironments. This is suggestive of the assimilation of GIS technology for a better appreciation of microbial oceanography. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.
Geomorphological behaviour of Sasihithlu, Mangalore coast, west coast of India
(2011) Nagaraj, G.; Karjagi, A.; Kumar, M.; Dwarakish, G.S.
Beach geomorphological studies have been carried out with help of conventional methods and remote sensing techniques. Conventional methods include beach profile surveys and beachwidth measurements whereas remote sensing techniques involved in utilization of satellite images, digitization and analyses. Beach profile surveys and beachwidth measurements are carried out at monthly intervals over a period of one year (September 2009 to September 2010) to understand dynamics of sediment along the coastal segment of 7km at Sasihithlu, north off Mangalore coastline. Six locations are selected based on their significant site characteristics along the coastal segment. It is observed erosion with steeper slopes during the monsoon and simultaneously deposition with flat and wider exposed slopes during the fair weather season. But the more drastic and dramatic changes are observed in the vicinity of Mulki-Pavanje rivermouth, since the rivers Mulky and Pavanje bring any kind of sediments irrespective of seasons. Because of this the profiles alter dramatically in the vicinity of rivermouth. It is estimated that the Sasihithlu beach has experienced a net loss of about 2515m 3/m, a net gain of about 3525m 3/m and hence a gain of about 1010m 3/m sediments in an annual cycle. Addition to conventional methods, remote sensing analysis is also carried out to detect the influence of rivers and their flow on rivermouth system in recent decades (1988-2009) with the help of satellite images and GIS tools. It is observed that the shifting tendency of rivermouth either south or north irrespective of seasons. However a detailed investigation on shoreline pattern showed a clear indication of shifting shoreline towards south. Therefore present study suggests to construct coastal protection structures on either side of the rivermouth, through that the damage to the property could be minimized. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.

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