Ballast Water Management Decision Support System - Global Maritime Transport and Ballast Water Management: Issues and Solutions - page 243

If the vessel is capable of properly conducting BWE on the intended route 7 for all
the ballast water intended for discharge, and the port State accepts the BWE method,
then the vessel does so and is clear to proceed. If not, then the use of BWEA or
alternative options are to be considered according to the level of risk posed.
Certainly, BWEA needs fi rst to be designated, and/or the alternative options need to
be studied, be available, and be feasible for vessels. Alternative options include bal-
last water reception facilities which may be made available in the port or an alterna-
tive discharge area may be found more appropriate for discharge of unmanaged
ballast water. If a ballast water reception facility would be made available, the vessel
would need to have additional piping installed to enable ballast water discharge in
such a facility. If possible, partial BWM is to be conducted still on the intended
route, and may be then continued and fi nalised in the BWEA or as alternative
method. Partial BWM means that on the intended route proper BWM is conducted
on a limited number of tanks, e.g., BWE according to the D-1 standard is conducted
for as many tanks as possible, e.g., four out of eight tanks intended for discharge,
and the remaining four are then left for BWE in the BWEA area, for alternative
management options, and some ballast if necessary may also be retained on board.
If a BWEA is designated according to the BWM Convention provisions, vessels
may use it if they sail through it on their intended route or if they choose to deviate,
though this is a decision of the ship's Master. Hence, it can be anticipated that ves-
sels will unlikely use BWEA by default; and even less so can it be expected that
vessels deviate or slow down to complete the BWE within a BWEA. Therefore, a
port State needs to have provisions in place to advise the vessel what to do. The
requirements to regulate the BWE in the relation to the BWEA are not deemed as
additional measures by the BWM Convention. However, most alternative options
will be deemed as such and need to be addressed according to the provisions of the
BWM Convention for additional measures (see chapter “ Policy and Legal
Framework and the Current Status of Ballast Water Management Requirements ” ).
One of the very important aspects for appropriate BWM is that a vessel does not
exchange the ballast water on board with water that is of a greater risk, e.g., areas
with toxic algae blooms, which may occur in the BWEA. Even if the water in the
BWEA is of the same risk level, BWE should not be conducted since the “older
water” in the tanks is expected to be of lesser risk than the “new” exchanged water
and can therefore lead to increased risk by adding, e.g., new nutrients or new organ-
isms to the ballast tank. In consequence, as by the IMO Guidelines on designation
of areas for ballast water exchange (G14) a BWEA should be monitored for
HAOP. In case of HAOP presence in the BWEA, the vessels need to be instructed
as appropriate to avoid BWE in this area (IMO 2006 ).
The following BWM options and consequences have been included if BWEA
and/or alternative BWM options are available:
7 The vessel may also consider a slight deviation and change “the shortest” route to be able to con-
duct BWE according to the BWM Convention limits, i.e., >50 NM distance of shore and >200 m
of depth.