Civil Engineering May 2021 | Vol 29 No 4

Civil Engineering May 2021 29 Q Q Develop an integrated framework for the monitoring and control of dredging activities, providing the regulatory authorities with the means to confirm compliance with environ- mental policies and associated require- ments. These included international agreements (specifically the London Convention) and national policies of Seychelles, as well as the European Investment Bank and International Finance Corporation guidelines and performance measures. Q Q Provide practical, achievable, and suffi- ciently detailed plans and performance criteria for the management of dredging activities that ensures compliance with the relevant environmental require- ments. This includes specification of the monitoring locations, the param- eters to be monitored, and relevant warning and action levels and associ- ated mitigative actions. Ultimately, these performance criteria inform the contractual requirements of the dredge tender documentation. Output The DMP produced for this study pro- vides detailed requirements in terms of: Q Q Dredging control management structures. Q Q The development of environmental baselines for monitoring activities. Q Q Monitoring during dredging, reclama- tion, and disposal activities. Q Q Mitigation measures should envi- ronmental impact exceed specified thresholds. Q Q Specific operations during dredging (e.g. noise, ballast water management, etc.). Q Q Post-dredging environmental surveys. The DMP is considered to have reached the defined objectives. The relevant compo- nents of the DMP have subsequently been incorporated into the EMP for the project. PROJECT STATUS The Port Victoria detail design studies have concluded, but the project has not yet gone out on tender for construction. Due to concerns related to the impact of Covid-19 on Seychelles’ economy, some further attention is currently being given to ensure optimum phasing of project.  Project team Promotor Seychelles Port Authority Principal design consultants Project Planning & Management Sub-consultants for marine design works WSP Africa for dredging (including nautical studies, dredging assessment and DMP) and port terminal layout and Zutari for quay wall, reclamation and pavement design Sub-consultants to WSP CSIR for environmental baselines surveys and assistance with nautical studies Figure 8 The predicted extents of acute impacts on corals and seagrasses (based on sediment concentration near the seabed) y-coordinate (km) 9 492.5 9 490.0 9 487.5 9 480.0 9 482.5 x-coordinate (km) 340.0 337.5 335.0 332.5 330.0 327.5 9 485.0 Zone of non-compliance 0–2 2–5 5–10 10–15 15–20 20–30 30–50 50–80 80–100 100–150 >150 Sediment concentration (mg/ℓ) 99 percentile