Abstract:
Studies on hydrodynamics are important since the hydrodynamic processes highly
contribute to sediment transportation in the coastal regions. Erosion in
Uswetakeiyawa coastal region of Sri Lanka has been a significant environmental
issue since 2000. The Coast Conservation & Coastal Resources Management
Department of Sri Lanka carried out artificial beach nourishment in 2012, and then a
set of offshore breakwaters was constructed in 2013 to protect the nourished stretch
of the beach. However, the beach was not developed to the desired extent. This
research was carried out to assess hydrodynamics to forecast the noted coastal
morphology in the Uswetakeiyawa coastal region. Wave data were gathered and
analyzed using "SWELLBEAT" software for 12 months, covering both the
monsoons. Further, "Delft3D" open source software was used to simulate the
hydrodynamics in the study area, and seasonal changes of coastal morphology were
analyzed for the study area using GoogleEarth images. The findings of this research
indicated that due to the strong wave action perpendicular to the coast during the
southwest monsoon, the beach was more vulnerable to erosion and there was no
sediment transportation to the beach from longshore drift during inter-monsoon
periods because sediments contributed from Kelani River were directly transported
to the ocean. Also, the predominant sediment transportation to the study area was
during the northeast monsoon.
