Silt curtain added to Saba harbour project

A floating silt curtain is being added at the Black Rocks Harbor construction site on Saba to stop fine sediment from spreading into surrounding wa­ters as work on the new harbour continues.

According to project manager Peter Bieremond of Public Entity Saba, the project’s environmental impact was studied before con­struction began, and various mea­sures have been implemented to limit and compensate for that im­pact. Turbidity caused by excava­tion and breakwater construction is being followed closely and has mainly been contained within the project area, he said.

Supervising engineer Luc Jor­dens of Dutch engineering com­pany Witteveen +Bos said silt­ation — fine soil particles — has been observed flowing out of the project area. “Though visible, the levels are low and kept within permissible limits,” he said.

Turbidity is being kept to a minimum through adjusted work methods and the construction of temporary bunds. It is monitored daily by a fixed monitoring buoy, as well as by manual measure­ments taken twice a day at three different locations. If permitted levels are exceeded, work is sus­pended.

Further restrictions apply during coral spawning season, including suspension of works, lower allow­able turbidity levels and more fre­quent measurements.

As part of the project’s environ­mental measures, approximately 1,400 corals were relocated from the project area to an area near Hole in the Corner. The corals are being monitored regu­larly, and their survival rate has so far been very high. Other compensation mea­sures include the addition of three marine protected areas to the Saba National Marine Park. Public En­tity Saba has also allocated funds to Saba Conserva­tion Foundation (SCF) and Saba Research Center to further protect marine life.

With work continuing and landside excavations sched­uled for the coming months, Bieremond said higher levels of turbidity may be expected. The silt curtain is being installed as an additional measure to further reduce the amount of fine material flowing into the surrounding waters.

The yellow curtain will form a floating barrier around the work site. It is made of per­meable fabric, measures 220 metres long and 10 metres high, and has been custom­ised to the project’s specifi­cations.

The buoys that will anchor the curtain have already been installed. The curtain has been prepared on land and will be towed into the water.

The Daily Herald.