Abstarct: 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. International transportation and port industry is responsible for 90% of the goods transported in the world. Increasing need for transportation resulted in invrease on ship size and number 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 portdevelopment. An ’ecosystem baxsed port design approach’ is a new way in the development of ports that consists of understanding the system at first and at big scales. 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 construction-phase of a port development, targeting sustainable measures at the system level in order to minimize harbor siltation. The ecosystem baxsed design approach (EBDA) is baxsed on philosophies (e.g. Building with Nature) and adopts theories from a PIANC-report on Sustainable Ports. 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. Also siltation minimization methods in ports are used to reach the aim of this research. In order to develop and evaluate the approach, a case study is selected. The port development project of Anzali, Iran is selected as most suitable to serve as a 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. Two measures are investigated by means of analytical studies and a hydrodynamic model (MIKE21). The focus is set on one measure: solving siltation issues in ports. Two alternatives were designed by means of KSO and KSM to solve siltation issues. KSM considers using jets to increase the current speed in harbor basin to prevent settling of sediments and KSO uses a bypass channel to separate rivers from harbor basin in order to stop siltation issues. The final design for port of Anzali is selected from comparing the two alternatives. Separating with bypass channel considered to be the final design and was introduced as the ecosystem baxsed design. In the evaluation, the finaldesign is compared to the traditional design. The application of the EBDA at Anzali, Iran results in a more sustainable port. Concluding this research, the ecosystem-baxsed design approach is considered to be an effective approach to reach a more sustainable design in the construction phase of port development. For future applications, great potential is expected in the development of sustainable ports. Further development 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.