Projects & Programs
Feasibility Study of the Port Dhamra-Chandbali Project, Shoreline Change and Wave Induced Sediment Transport Analysis, Dhamra Orissa, India
In support of a feasibility study for a port construction project at Dhamra Orissa, India, PNNL staff, while at another organization, evaluated sediment transport and shoreline change due to wave activity. Although the existing shoreline was in equilibrium, there was concern regarding the change in oceanographic environment that would occur following the port construction. The project would involve dredging of a large navigation channel and construction of a dike perpendicular to the shore.
The Generalized Model for Simulating Shoreline Change (GENESIS) was used to estimate changes in the shoreline due to oncoming waves. The shoreline change study included wave frequency analysis of deepwater wave data, wave transformation from deep water to shallower depths, near-shore wave analysis using the RCPWAVE model and GENESIS analysis of cumulative changes to the shoreline. The length of each cell of the GENESIS model was approximately 133 m in the long-shore direction. The shoreline change was based on volumetric analysis of the amount of sand entering and exiting each model cell. The long-shore sediment portion of the model combined sediment transport produced by breaking waves and sediment transport generated by a long-shore current resulting from a long-shore variation in the breaking wave height. The proposed dike for port protection was assumed to act as a groin that was impervious to the waves and high enough to avoid overtopping.
The shoreline change analysis was conducted for the proposed dike conditions and the results were compared with existing conditions. Construction of the dike would initiate accretion along the dike; however, the shoreline change would be restricted to the areas along the dike and just upstream of the dike. The results showed that the port development would have limited effect on the shoreline, and accretion would be negligible compared to the annual maintenance dredging already anticipated for the port.
Project Highlights:
- The project demonstrated that a port construction project would cause limited change in the long-shore transport and require negligible maintenance dredging, which showed that the project was feasible
- PNNL staff developed a tool to predict shoreline change in response to proposed port development activities
- Simulation results showed that one of the proposed alternatives (dike in the north channel of Dhamra River) could lead to limited sediment accretion.