Textural characteristics of foreshore sediments along Karnataka shoreline, west coast of India

Abstract

Grain character analysis of beach sediments along three selected beaches (Pavinkurve, Kundapura and Padukare) of Karnataka coast, west coast of India is carried out in the present study. The objective was to identify the textural behavior of beach sediments during an annual cycle from March 2008 to February 2009. Grain characteristics such as central tendency, sorting, kurtosis and skewness were estimated using GRADISTAT and discussed. The maximum (62%) sediment samples were medium sand with unimodal and bimodal characters at all the three beaches. The median values varied in between −0.04 ϕ and 2.74 ϕ with an average value of 1.61 ϕ. The beaches were characterized as well sorted, moderately well sorted and moderately sorted sediment environments. Sediments were identified as fine skewed to coarse skewed with platykurtic, mesokurtic and leptokurtic characters. Grain characteristics varied spatially and temporally along with beach orientation, foreshore slope and wave action. A negative correlation between mean and sorting is identified for maximum number samples along the study region but not very significant. The study shows that the sedimentary environment at Kundapura were influenced by relatively high wave action compared to Padukare and Pavinkurve beach and the beaches were under erosion or non-deposition with strong winnowing process.