$30m of dredging among options to enlarge shipping channels

WEDNESDAY, SEPTEMBER 21: The two main shipping channels into Bermuda could require extensive dredging, costing $30 million in order to accommodate larger cruise ships.

According to a study commissioned by Government several “high spots” in the North Channel do not meet ship handling and navigational safety guidelines for the larger Tier 4 cruise vessels.

While the current depth of the South Channel prevents almost all cruise ships from using it.

The report suggests the South Channel would require dredging from its depth of 8.5-9.5 metres to 11 metres, at a cost of an estimated $24 million.

Three options were identified in relation to the North Channel, including deepening, widening and realigning it.

The cost of this dredging work is estimated to cost around $10 million.

The report states: “The North Channel currently accommodates most cruise vessels up (to) and including Tier 4.

Manoeuvrability

“However, ship handling and manoeuvrability is compromised in several sections of the channel due to physical and operational issues.

“Navigation issues of transiting the North Channel and ‘The Narrows’ are generally limited to channel depth, width, and alignment constraints in ‘The Crescent’ region and the approach to Grassy Bay.

“Channel widths and water depths in remaining locations of the North Channel and in ‘The Narrows’ region generally meet ship handling and navigational safety guidelines for current and projected cruise ships that would utilize this channel including Tier 4.

“However, there are several ‘high’ spots in the channel that do not meet the guidelines.

“Modifications in the width and depth to the North Channel may be required in certain reaches to more safely accommodate Tier 4 vessels.”

The study suggests Government is discussing accommodating a Tier 4 ship, such as the Freedom-class, in the North Channel.

But it reveals that the Bermuda Pilots Association have expressed concern that navigation of Tier 3 and potentially Tier 4 ships may be compromised along stretches of the channel due to high points, channel bank suction effects in White Flats and channel alignment near Brackish Pond Flats.

It states: “Three alternatives are proposed as potential solutions to the issues experienced in the North Channel.

“Depending on the future criteria for ship sizes and manoeuvering requirements, various aspects of each proposal or a combination thereof may be chosen. Any decision would also require environmental considerations.

“The first alternative calls for dredging a total of 5,755m3 of material in four specific locations between White Flats and Royal Naval Dockyard to achieve channel depths of at least -12.5m CD.

“The second alternative proposes a more extensive modification programme at White Flats. The area would be widened to 215m and dredged to a minimum depth to a depth of -13.5m CD. This would see the removal of some 168,630m3 of material, which includes a portion of reef removal.

Realignment

“The third alternative which also encompasses the North Channel between White Flats and Royal Naval Dockyard is similar to the first, but also calls for realignment or straightening of the channel and dredging in three additional locations with a total of 30,880m3 of material removed.”

The study also looks into what would need to be done to the South Channel to accommodate cruise ships.

It says modifications there require dredging but little, if any, widening.

It states: “The primary access improvement to the South Channel is deepening to facilitate transit of Tier 1 and Tier 2 ships.

“As previously discussed, channel depth guidelines for Tier 1 and 2 ship classes requires the South Channel be dredged to -11.0m CD.

“Dredging to this depth extends a distance of approximately 6.5 km along the west section of the South Channel as it approaches Grassy Bay. The average dredge cut is 2m. Dredging will also be required offshore of Crawl Point, impacting patch reefs. 

“The proposed dredging will likely require the excavation of the 934,150m3 of seabed, with little direct removal of coral reef.”