Abstract:
Beach nourishment is a soft engineering solution that is
increasingly used to combat erosion in a sustainable manner. Sri Lanka's first major
Beach nourishment project was carried out over a 1.8 km stretch in the
UswetakeiyawaPalliyawatta area, by the Coast Conservation Department of Sri
Lanka (CCD). The Project was conducted in January 2012 and 300,000 cubic meters
of offshore sand pumped using a dredging vessel was used to nourish the stretch of
eroded beach with a total project cost of USD 300 million. This research was carried
out to assess the performance and to forecast the future performance of the above
nourishment project. Topographic data and grain size data were gathered and
analyzed over a period of six months spanning an entire seasonal cycle. Satellite
imagery spanning a much larger time period were also analyzed and
complemented with the field data. The findings of the research indicate that due to
incorrectly oriented sand retention structures and the incorrect grain size of
nourished sand, the nourished area is currently undergoing rapid erosion.
However, it is forecasted that the beach will come back to its pre-nourished stage
after a period of 12 months. This will result in the exposure of a beach rock at the
mean sea level and will cause the beach to lose its recreational and aesthetic value,
and to prevent this and to retain the nourished sand, the correct orientation of the
retention structures and the appropriate grain size for nourishment are proposed.
Citation:
Azoor, R.M., De J Seneviratne, M.T.M.R.I.C., Saranya, R. Thenugaadevy, P., Gamage, G.S.M., Premasiri, H.M.R., & Ratnayake, N.P. (2015). Performance forecasting for the beach nourishment project at Palliyawatta-Uswetakeiyawa Sri Lanka. In P.V.A. Hemalal (Ed.), Proceedings of the 9th Annual ERE Research Conference on Earth Resources Management (pp. 58-63). Department of Earth Resources Engineering, University of Moratuwa.
