Sediment characteristics in relation to changing hydrography of Cochin estuary

Sediments of a Cochin estuary (Kerala) were studied in relation to changing hydrographical conditions. Seasonal spatial grading of particles as sand, silt and clay was observed. Contents of organic carbon, phosphorus and iron in sediments were closely studied in relation to hydrographical changes and attempts were made to describe the textural distribution on the above basis. The northern arms of the upper estuary were mainly composed of sand particles. The lower estuarine regions indicated seasonal abundance of sand during monsoons pointing out to bedload movement. Otherwise, this area was predominantly covered by clay, silt size fractions. Surficial sediments also indicated variations in texture resulting from detritus settlement influenced by mixing conditions in the estuary.