The project to construct a new harbor at Black Rocks is proceeding. The existing dirt road has been widened and rock catchment benches have been created to provide a safe access to the Black Rocks area. The intention is to soon start the construction of a grouted rock wall along the road and to initiate preparatory works for utilities. Various studies have now been completed, which provide important information for the further elaboration of this comprehensive project, financed by the Dutch government.
The archaeological site survey by the Saba Archaeological Foundation SABARC has been concluded. Several artifacts were found in the Black Rocks area, including two old ship cannons which will be moved to a dive site. The soil investigation and the laboratory tests of the soil samples withdrawn from the land and sea bed are finished. The field work by a team from Geotron of the Netherlands was concluded in September last year after which laboratory tests were done on the soil samples.
Construction methods
The outcome of the soil investigation helps to determine which construction methods are feasible for the breakwater. One of the possible construction methods, a cofferdam breakwater, requires driving of piles. The soil investigation shows that this could be a challenge at the Black Rocks location, because of some large boulders situated in the deeper layers of the seabed. A specialized company has been asked to advice on this aspect.
Through physical model tests at the University of Ghent, Belgium, the robustness of different construction methods was tested. For this purpose, two scale models, a vertical (caisson/cofferdam) and a berm (rock) breakwater, were exposed to different wave conditions, up to a category 5 hurricane.
These test results will serve as input for the general design of the harbor by Witteveen+Bos of the Netherlands and for the marina design by ATM from the United States. Harbor project manager Ton van der Plas explained that even though the physical model tests showed that the wave forces of a category 5 hurricane were five times lower at Black Rocks than at Fort Bay, the wave impact is still very heavy.
Environmental Impact Assessment
As part of the permit application an Environmental Impact Assessment (EIA) was carried out by Ecovision from Curaçao. The extensive report is ready in draft format, but still needs to be discussed with the stakeholders. The assessment addresses the environmental impact of the harbor development on both the landside and marine life. Focal points include the colonies of elkhorn coral (Acropora Palmata) in the project area, which is a protected species. These coral colonies will have to be relocated before the harbor construction starts.
To determine the best relocation method and location, the Saba Conservation Foundation (SCF) runs a pilot project. Fragments of four coral species were moved to two different locations. So far, monitoring of the fragments has shown that the best location to replant the corals is ‘Hole in the Corner’, east of Black Rocks. The EIA also points out the fact that the cliffs of St. Johns, close to harbor development, are a nesting site for the protected Red-billed Tropicbird (Phaethon aethereus). Measures must be taken to avoid disturbing these birds during the construction of the harbor.
Erosion risk
Another important topic in the EIA is the risk of erosion, which has a negative impact on the corals. The proposed new harbor will be constructed in a zone that is already affected by uncontrolled erosion, largely caused by roaming goats. Development of the area will further impact the still vegetated land. This aspect must be tackled trough the goat control project and revegetation of the area.
The EIA concludes that a major project such as a harbor development is bound to have an adverse impact on nature. The objective is to keep this adverse impact on the environment to a minimum and to balance this in the decision-taking process with the economic, social and safety impact.
On May 6, Van der Plas presented all these latest developments to the Island Council. According to Van der Plas, there was a lot of interest and many questions were asked. The next few months the project will focus on the detailed design, the permit application and the tendering procedure. Tendering for new harbor is scheduled to start before the end of this year.