Influence of morphodynamic variability over seasonal beach sediments and its probable effect on coastal development

Abstract

Seasonal variations and effect of oceanographic processes such as erosion and/or accretion along beaches are important to understand their impact on coastal morphological variations. Detailed investigations were taken up to analyse the volumetric and morphologic variations of the beaches between Pirwadi (latitude 16° 12′ N, longitude 73° 26.55′ E) and Sarjekot (latitude 16° 05′ N, longitude 73° 27.80′ E) of South Maharashtra, Central West Coast of India. This stretch is known for its rich deposits of ilmenite, magnetite and chromite. This study is based on the results of seasonal topographic profiles carried out between October 2004 and December 2005. The volume variations of the sediments, i.e. an account of accretion and/or erosion, were estimated considering the October 2004 profile as the base reference, over which the values of other seasons are compared. The results of beach profiling from Pirwadi to Talashil indicate the seasonal variations in the beach configuration and the gradient. In the studied areas the vulnerable areas are Tondavali, Talashil and Pirwadi in a decreasing order of erosion while Bagwadi shows lesser erosion. Several reasons can be attributed for these erosional trends. Among which the prominent are rip currents, wave dynamics, variable coastal configuration, beach gradient and temporary monsoonal seaward flowing streams. In contrast, significant deposition occurs throughout the year at Hirlewadi due to sediment transported by due south by littoral currents. Therefore, considering the sensitivity of the fragile coastal system, future developmental activities (mining, tourism, etc.) need to be planned in tandem with the required protective measures such as construction of reinforced concrete curved wall and geotextiles.