Ballast Water Management Under the Ballast Water Management Convention - Global Maritime Transport and Ballast Water Management: Issues and Solutions - page 95

BWE should be conducted as far from nearest land as possible, and in all cases at
least 50 nautical miles from nearest land and in waters of at least 200 m depth
(IMO 2004 ).

Ballast Water Exchange Areas

In sea areas where these BWE depth and distance requirements cannot be met, the
port State may designate a ballast water exchange area (BWEA). This should be
done in consultation with adjacent or other states, as applicable. Any such designa-
tion should follow the principles of Guidelines on Designation of Areas for Ballast
Water Exchange (G14).
However, a ship shall not be required to deviate from its intended voyage, or
delay the voyage to conduct BWE. In contrast, a port State may require a ship to
deviate from its intended route or delay its voyage in case a designated BWEA has
been established. The BWE activity for each tank should not start if the process can-
not be fully completed.
In general, ships should follow the G6 Guidelines and shall only be required to
comply with any BWE requirements if those would not threaten the safety or stabil-
ity of the ship, its crew, or its passengers because of, e.g., adverse weather, ship
design or stress, equipment failure, or any other extraordinary condition.
Vessels operating in coastal areas are unlikely to meet the distance (200 nm or
50 nm distance from nearest land) and water depth (200 m depth) requirements of
the BWM Convention. Further, routes may be too short to conduct a complete BWE
of all ballast tanks intended to be discharged in the port of call. Management options
for those vessels may therefore be based on a selective approach, i.e., use a desig-
nated BWEA or by granting exemptions based on RA (see chapter “

Risk Assessment

in Ballast Water Management ” ).
The rationale for the BWEA designation is that it provides an area where ships
can safely exchange ballast water as a risk reducing measure while at the same time
minimising harmful environmental effects. However, next to shipping and nautical
aspects, the challenge is to identify such areas from a biological perspective. It is
understood that coastal BWEA pose a higher risk of species introductions compared
to mid-ocean exchange, but at the same time it may be preferred to use specially
designated BWEA rather than to discharge unmanaged ballast water in a port or
across the entire coastal area.
Strong concerns have already been voiced that the designation of near-shore
BWEA may expose certain regions to additional ballast water discharges, which
may pose a risk to those ballast water receiving environments. This is why BWEA
need to be selected very carefully using RA to prove it is environmentally safe. Ideal
would be a BWEA with off-shore directed water currents, it should be as far from
nearest land and as deep as possible, free of pollution or HAOP. When these
requirements are met the BWEA may be considered environmentally safe and
effective. When considering shipping aspects, the BWEA needs to be designed as
large as possible and as close as possible to shipping routes (David 2007 ).