Find in Library

Muttukadu backwater form a complex system of shallow estuarine network spread over an area of 0.87 km2 meant for fishing and boating activities. The study area is connected to the sea by a bar mouth, the width of which is variable from a few meters to 200 m in different months. Mouth closes due to sandbar formation from March to September. A combination of reduced river discharge, the build-up of an oceanic bar as a result of onshore sediment transport by long-period swell wave action during summer, cause the formation of sand bar.  Sediments are the major sink for chemical components of water bodies and sediment chemical analyses afford methods for measurements of the quality of overlying water and the levels of potential pollutants. Station 1(0.5 km away from the mouth) and 9 which is in the sea is always sand dominated as they are influenced by the nearshore dynamics. The saline sea water, which enters the estuary, resuspends the flocculated sediments at the mouth and transports the fine floccules to the water column during the open condition. pH (7.7) of the sediment is high during monsoon season. The total nitrogen (4.7µg/L) of sediments is higher during summer season due to the oxidation of dead plant organic matter, which has settled on the top layer. Total Phosphate shows a positive correlation with silt. Phosphorus load is high in the stations 5, 6, 7 and 8 is 2.3, 2.1, 4 and 2.5 (µg/L) which is located in the upstream of the backwater and in Buckingham canal compared with the mouth region, indicating that the environment is substantially influenced by local sources of sewage, industrial effluent etc.