In the present study the research has been focused on the textural characteristic of the river bottom sediments grain size is the fundamental descriptive measure of the sediments and sedimentary rock large part of information about the sedimentary particles mode of transport and deposition can be obtained from the grain size and the sedimentary environment can be identified by the grain size parameters. This paper determines the average content of clay, silt and sand in the bottom sediments of Arasalar River as well as the sediment statistical parameters. A total of twenty bottom sediments samples were collected during four seasons during the year (2008-09) covering the mouth, estuary and the fresh water zones of the Arasalar river. The result shows that the percentage of sand is more compared with silt and clay during all the four seasons. The concentration of silt and clay is more during summer than the monsoon season which shows the influence of rainwater. During summer season the mean size shows fine sand in dominance, the standard deviation values shows poorly sorted and the skewness indicates strongly fine skewed and the kurtosis value indicates mesokurtic in nature whereas during monsoon season the mean value shows medium sand dominance. The standard deviation indicates poorly sorted in nature and the skewness shows nearly symmetrical and the kurtosis indicates mesokurtic in nature. The difference in the grain sizes may be due to the low energy condition and the influence of rainfall.
