Abstract:
Grain size distribution and textural parameters are spectacles to interpret the sediment movements and depositional
processes of lagoonestuarine systems that are intermittently open in flood control measurements. A spatial grain size distribution study
was carried out to investigate the morphologically controlled sediment movement and deposition of the lagoonestuarine system of the
Eastern coast, Batticaloa, Sri Lankawith a specific emphasis on inlet management. A total of 51 surface sediment samples of the
lagoonestuarine system of Batticaloa were collected and analyzed for grain size distribution and textural parameters. The results
revealed that a marked relationship between lagoonestuarine morphology and the mode of the particle size distribution with respect to
the sediment deposition and inlet flows. Statistical parameters are further confirmed from the grain size distribution curves which
indicate that the sediments of beach and inlet associated areas have medium to coarse size positively skewed platykurticnature. However,
barrier deposits and shaded areas have medium size negatively skewed leptokurtic nature. The prominent sediment components of
barrier deposits and shaded areas as well as beach and inlet associated areas reflect the morphological transition of lagoon environment
to estuarine environment. The subordinate components of sediments show two different depositional environments indicating inlet
changes. The inlet opening and the closure depends on the intensity of river flux and marine processes. The grain size distribution and
morphology parameters of studies samples show a clear relationship which indicate both anthropogenic and natural processes control
the changes of inlet of the lagoon estuarine systems.
