“Maritime Cities” is a project conceptualised by the CHEC Port City Colombo Ltd. For this project, CCCC-FHDI Engineering Co. Ltd. is responsible for the design of the Maritime Cities, which consists of a revetment in the north and an artificial beach protected by coastal structures in the south. To obtain the detailed design input conditions, to investigate the stability of the proposed artificial beach and to analyse the impact of the development on the neighbouring coastline, numerical studies have been performed by CDR using the Delft3D modelling suite.
To generate the design wave conditions for structural designs and to generate the input (averaged) wave conditions for the morphological modelling, a detailed wave assessment was done to translate a 30-years offshore validated time series to the area of interest. This model was calibrated using available measurement data. Input wave conditions for the morphological modelling were generated by a statistical analysis of the relevant morphological conditions, resulting in a combination of representative morphological wave conditions every month. Together with tide, this wave data was used as input for the 2D numerical wave, current and morphological model. The model was run for a period of 1 year + 10yr RP storm condition to determine the stability and coastline changes of the beach pockets and the neighbouring coastlines. In addition to this, the exchange capabilities of the beach pockets were determined for the different seasons and the theoretical dispersion of a hypothetical concentration coming from a nearby sewage outlet was computed for the area of interest. Using the numerical modelling results the design studies can be further detailed, the stability of the beaches was verified and the impact of Maritime Cities on the neighbouring coastline and the water exchange of the design was determined.