Ecosystem-based port design: An approach for sustainable port development

The world population is growing. Together with the population, the need for resources is growing, as is the need for the transportation of these resources. A significant part is carried out through marine transport, directly relating to the increasing need for port development. All over the world, a shift increasingly occurs towards applying sustainable measures. The combination of these events, results in the context of this research: Sustainable port development. This research entails the search for an implementation strategy for sustainable port development: An 'ecosystem-based port design approach' is devised. This approach is applied working top-down, with a division on three levels; system, construction and material level. The focus of this research is set on the implementation of sustainability in the design-phase of a port development, targeting sustainable measures at the system level. The ecosystem-based design approach (EBDA) is based on existing philosophies (e.g. Building with Nature) and adopts theories from a PIANC-report on Sustainable Ports [Vellinga et al., 2014]. Ecosystem services are used for the evaluation of the approach. The approach consists of five steps: (1) Understanding the system, (2) Designing alternatives, (3) Modelling alternatives, (4) Evaluating alternatives and (5) Final design. In order to develop and test the approach, a case study is executed. The port development project at Tema, Ghana is selected as most suitable to serve as a test case for the application of the approach. Steps one through five are applied to the case and this thesis shows the difficulties, challenges, strengths and opportunities that are encountered along the way. For the case study, potential measures are developed during a brainstorm session. Five measures are investigated by means of analytical studies and a hydrodynamic model (Delft3D). The focus is set on one measure: the beneficial re-use of dredged material from the port basin and approach channel. Using the dredged material, a nourishment is redesigned to maximise its lifetime and to minimise the sediment transport rates. The sediment transport rates are predicted using Delft3D and by inter-comparing the ecosystem-based nourishment design to the design as proposed by Boskalis, a revision is proposed. The reclaimed area is enlarged and the lifetime doubled. The final design for Tema consists of a revision of the nourishment, includes possibilities for lagoon development, contains open possibilities for the development of a so-called 'plastic trap' and proposes to use the Building with Nature seabed landscaping technique in the offshore dredging activities. The measure that entailed preventive dredging of a scour hole is dropped, as model results show small sediment transport rates over the breakwater into the port area. The potential gain consequently diminished and the measure is excluded from the final design. In the evaluation, the ecosystem-based design is compared to the traditional design that is used as the starting-point for the approach. Strengths, weaknesses, opportunities and challenges are compared in a so-called SWOC-analysis, wherein the ecosystem services are used as indicators (economy, ecology, society). For this case study, the ecosystem-based design shows improvement on all aspects of the ecosystem. The application of the EBDA at Tema, Ghana results in a more sustainable port. The process of applying the EBDA is also evaluated and lessons learned are derived. Finally, the approach itself is evaluated. Concluding this research, the ecosystem-based design approach is considered to be an effective approach to reach a more sustainable design in the initial phase of port development. For future applications, great potential is expected in the development of sustainable ports. Further development of the EBDA can be achieved by structurally applying the approach to different phases of port development, in different areas over the world, for varying functionality of ports and for different users. By comparing differences and similarities, a generally applicable approach can be developed. Eventually, a practical framework can be constructed, containing sustainable measures that are applicable to specific port development projects.Ports & WaterwaysHydraulic EngineeringCivil Engineering and Geoscience