Seasonal distribution of surface sediments and hydrodynamic conditions in Zuari estuary, Goa, Central West Coast of India

Abstract

The seasonal distribution of surface sediments and hydrodynamic conditions prevailed during their deposition have been studied within the Zuari estuary. Surface sediments collected from 18 stations all along the length of the Zuari estuary. during three different seasons viz. monsoon, post-monsoon and pre-monsoon, were analyzed for sand. silt, clay and organic carbon. The study revealed that upper half of the estuary is mostly dominated by sand while the lower half is enriched with the clay and silt components in all the three seasons, with minor variations. Organic carbon is also noticed to be higher in the lower half of the estuary with a general decreasing trend towards the mouth. Further, finer sediment distribution and higher concentration of organic carbon is specifically noted during pre-monsoon season compared to other two seasons at most of the stations. Significant positive correlation between organic carbon and clay (0.7603 - Average of three seasons) supports the association of organic carbon with finer sediments. However, sand shows inverse relationship with organic carbon. Based on sediment characteristics, an attempt has been made to understand the hydrodynamic conditions prevailed in the Zuari estuary in three different seasons.