Comparative Grain Size Analysis on Sediments of Bhagirathi & Alaknanda River

Abstract

Grain size analysis of clastic sediments refers to a set of logical approach conducted in the laboratory to determine the size of diverse range of collected sediments of a particular region or area. The main objective of this approach is to classify sedimentary environments. The above mentioned objective can be achieved by many standard techniques like sieving, laser granulometry and various statistical tools which employ arithmetic, geometric and logarithmic calculations.

In this study, twenty two recently deposited channel sediments were collected from the Bhagirathi and Alaknanda River. Gradation test was performed on the nine samples (SD 11 to SD 19) to get individual class wise sieve weight to assess the grainsize distribution. After that, raw sieve weights were converted to individual weight percents & cumulative weight percent to plot two types of curves i.e. Frequency Curve and Cumulative Curve on log probability scale, for each sample. Both graphical and mathematical data-reduction methods were applied on the obtained data to determine Mean, Standard Deviation, Skewness and Kurtosis. A comparative study was being made on the results obtained by both the methods.