Damage from Military Anchoring in the Lagoon

Approximately 10 ships of the Maritime Pre-positioning Ship Squadron (COMPSRON ) TWO are deployed to Diego Garcia at any one time, where they remain at anchor in the lagoon.

These ships contain equipment and supplies to allow rapid deployment to areas of operations and combat in the Indian Ocean and Middle East. They were used in the Gulf Wars in 1991 and 2003.

The ships occupy anchorages in the northern sector of the lagoon.

In 2008 the BIOT Government commissioned a report into the effects of this ship anchoring [Sheppard C.R.C, Smith S., Turner J.R., Marx D. (2008) Coral and sediments in the lagoon in Diego Garcia and effects of ship anchoring - Link to Report].

The report found that :

1. Anchoring is apparently confined to a series of anchoring locations, partly to limit area of damage. But several different plans of anchor circles have been found which, together with significant anchor damage observed between present circles, means that anchoring has taken place over most of the anchorage areas, not just in designated sites.
2. Two thirds of the anchorage area and one third of the lagoon's area of richest coral, is anchored on at various times and intervals.
3. It is estimated that anchoring in the present manner causes loss of up to one third of corals in the coral-rich northern basin, and up to two thirds of that in the whole lagoon.
4. Understanding [of anchor damage] long ago may have been one factor leading to the installation of 17 large moorings in early days of the military use of Diego Garcia. Most, however, were removed shortly afterwards, when anchoring commenced. Two mooring remain and are used in conjunction with the POL [Petroleum, Oils and Lubricants] pier.

In 2013 steps were taken to limit anchoring to 12 locations only.