Environmental Engineering Reference
In-Depth Information
the world merchant shipping gross tonnage (for an update visit Status of Conventions
at
www.imo.org
)
.
Nonetheless it must be emphasized that effi cient ballast water management
(BWM) does not imply the prevention of HAOP introductions at any cost, thereby
laying an additional burden on and generating higher costs for the shipping industry.
Undoubtedly, the cost of prevention should not be higher than the benefi ts it
generates.
Conditioned by the lack of on board installed BWMS on existing vessels, ballast
water exchange (BWE) is today the most widespread available BWM method also
approved by the BWM Convention. Nevertheless, ballast water exchange has draw-
backs which make it ineffi cient or even impracticable under certain conditions (e.g.,
on shorter voyages where “intended routes” are too close to the shore, attain insuf-
fi cient water depths, a lack of knowledge of the presence of HAOP in the water
exchange area). Further, other issues related to an effi cient BWM system arise
which are outside of the vessels' responsibility, e.g., targeting of vessels for ballast
water sampling as part of port State compliance control procedures.
As a result, countries wishing to protect their seas, human health, property and
resource from the introduction of HAOP with ballast water are confronted with a
signifi cant challenge. Given that BWM requirements may result in ineffi ciencies,
lower safety margins and higher costs in the shipping industry, the reasons
described above make the 'blanket approach' (i.e., mandatory BWM for all ships)
unjustifi able in a range of different local conditions. An alternative to the blanket
approach is the 'selective approach' where BWM is required for selected vessels.
This selection should be based on a suite of information needs and procedural
decisions to aid transparent and robust BWM decisions. Such systems have been
developed in a variety of applications where a large number of complex decisions
must be made in a consistent, transparent and defensible manner. These systems
are typically referred to as decision support systems (DSS). Such a DSS as applied
to BWM implies adjusting the intensity level of BWM measures to each voyage
based on risk assessment (RA), and recommends also compliance monitoring
and enforcement (CME) actions (see chapters
“
Ballast Water Management
A BWM DSS provides essentially needed support to responsible agencies for
the implementation of effective BWM measures. The introduction of BWM prac-
tices adds burden and costs mostly to the shipping industry, on the other side,
their effi ciency is critical. In light of these, the BWM DSS needs to provide for
(David
2007
):
-
an effective protection against the introduction of HAOP;
-
proper RA as one of the key elements of the BWM DSS;
-
local specifi cs are addressed in direct relation with the effectiveness of the BWM
(e.g., geographical, hydrological, meteorological, important resources, shipping
patterns, regulatory regime);
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