The coastal sites of Ramnagar-I and Ramnagar-II Administrative Blocks (Kanthi Coastal Plain), Purba Medinipur District, West Bengal, India, reveal various morphological features, which are represented by four categories of surface formation under different processes in the present study through a contour plan with 50 cm contour interval. The first category of landform being some isolated ridges with above 10 m elevation, which are stretched out in a linear pattern parallel to the modern shoreline behind Ramnagar-Deuli beach ridge section. The second set of landforms of the area which ranges from 7 m to 10 m elevation from the MSL is extended in the form of sandy terrace and continuous sand ridge surface along the sides of the first category landform. The third category of landform is visible along the edges of the second category of continuous sand ridge topography in the form of an extensive sandy tract with the reactivated sand surface.Last category of the ancient surface with an elevation of 2.5 m to 5.0 m above MSL is also clearly visible from the wide valley flat surface depressions in between the Contai-Paniparul beach ridge section and Ramnagar-Deuli beach ridge section at present. Some crenulated ridges of sandy sediments observed in the the present contour plan, particularly along the bank of abandoned channels. These are most probably evolved in the ancient period by natural levee depositions from various fluvio-tidal channels of the coastal plain. They are also categorized into older natural levees and younger natural levees delineated from the tonal contrasts of images and field verification of lose sediments. The older natural levees represent oxidized soils and the younger one represents the grey white color of sediments. Tidal prisms are the result of spring time tidal waves, keeping pressure on the seaward sides and spill over the backshore area by entering into the tidal channels at the time of high tide in the coastal belt. The study reveal the effects of significant increase of tidal prism estimated from 1990 to 2017.

An assessment of geomorphic evolution and some erosion affected areas of Digha-Sankarpur coastal tract, West Bengal, India

Seasonal morphological variations and effect of oceanographic processes such as erosion or accretion along beaches are important aspects to understand the sand budget. The nature of the beach and their seasonal cyclic changes are probable reasons of seasonal morphological variations. The primary objective of the present study is to estimate coastal beach sand budget using Geoinformatics techniques. The study area is 113 km long coastal belt covering parts of Midnapore–Balasore coast. The field data has been collected using GPS and Theodolite, following standard cartographic techniques. Besides, Remote Sensing and GIS techniques have been used in identifying the coastal features, mapping and spatial analysis. Therefore, eighteen beach profiles have been taken during the post and pre-monsoon seasons of the year 2008 and 2009. Within the specific zones, beach erosion and/or accumulation between post and pre-monsoon season has been quantified. The result shows that up to pre-monsoon season, the beach is significantly recovered with gradual decrease in beach gradient. Further, along each profile Digital Elevation Models corresponding to post and pre monsoons periods have been generated, which has subsequently utilized in the estimation of beach recovery along each profile and also estimation of beach sand budget of the study region.

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GIS based beach sand budget analysis through seasonal beach profiling using cartographic techniques

Exploration of chronological development of coastal landscape: A review on geological and geomorphological history of Subarnarekha chenier delta region, West Bengal, India

Seasonal morphological variations and effect of oceanographic processes such as erosion or accretion along beaches are important to understand the nature of the beach and the cyclic changes occurring during different seasons. These studies are more significant in the areas where rich beach placer deposits are occurring. This will help in understanding replemishment of these heavy minerals in the area of interest. This report describes results of similar studies (beach profiling) carried out at Malvan and Kotharwadi coast, which is in southern part of Maharashtra along central west coast of India. Malvan is one of the most important prospective area for the heavy mineral placers of Ilmenite and Magnetite. Several techniques are available for collecting these data using different instruments. The required data was collected by using DGPS (Differential Global Positioning System) and Automatic level (Carl Zeiss make). following standard surveying techniques. Beach profiles at ten sites along Malvan and Kotharwadi beaches have clearly shown the specific zones of sand erosion and sand accumulation at various periods. Maximum sand accumulation is found at BP: 3 near Tondavali village during Dec. 2005, resulting to deposition of sand/mineral of volume upto 61.92 cu.meters, which is 57.56% more than the first season observation, which was in Oct. 2004. Another significant observance is the highest erosion found at BP: 4 near Tondavali village during Aug. 2005, resulting in loss of volume of sand/mineral upto 314.05 cu.meters, which is 139.5% less than the first season observation, which was in Oct. 2004. Such variations are due to oceanographic processes, operating in the area. This report analyses the field data collected at different seasons and presents the results with final processed beach profile graphs. The report also highlights the method involved and the instruments used in collection of the field data and processing.

S.S. Gaonkar

Papers

Seasonal beach profiling along Malvan and Kotharwadi coast , southern Maharashtra, central west coast of India.