Ballast Water Management Decision Support System - Global Maritime Transport and Ballast Water Management: Issues and Solutions - page 239

Fig. 8 Decision (2) on vessel trustworthiness (Enhanced after David 2007 ) (This fi gure can be
downloaded from http://extras.springer.com/ )
For the purpose of this BWM DSS, the BWRA model presented in chapter “ Risk
Assessment in Ballast Water Management ” is to be applied to assess the level of risk
for selective BWM measures. When the level of risk assessed is extreme, high or
intermediate, it is deemed not to be acceptable (see Fig. 11 ).
Ballast Water Management Process
BWM requirements apply to a vessel when the risk posed by the ballast water
intended for discharge is deemed unacceptable. This includes the selection of a
feasible (for the vessel) and acceptable (for PSA) BWM method according to the
level of risk posed, which is followed by consequences if the required BWM mea-
sure is not applied.
There may be different instances when a vessel may not be able to conduct BWM
(e.g., route too close to the shore, bad weather and sea conditions, some issue with
the BWMS). In those instances, the PSA needs to take a decision whether to allow
the vessel to discharge unmanaged ballast water, or use (if available) some alternative